Comments: Eh. Not worth the extra cost. 4.5 player string my own racquets with this as a cross. Some kind of a poly in the mains. This string definitely got shredded with whatever by whatever poly main I used Hyper-G, Cyclone, etc. Totally to be expected. However, I didn't except the multi to loose so much playability as it did. It felt like playing with one of my favorite syn gut strings Gosen Micro. On feel alone, still think I think I would prefer the Gosen because it stays relatively crisp until the end. X-One looked like and felt like I was playing with a shredded rope. And with that kind of playability, why not go for the cheap syn guys? I feel the playability of Volkl and Gamma multis are a much better deal.
From:Ian, 8/18/18

Comments: I am a 4.5 player using a Donnay Pro One Pentacore racquet with an open string pattern. These strings are simply the best comfort, power, feel combination on the market. Between the flexibility of my frame and the comfort of these multifilaments, I experience no arm troubles even after having multiple elbow and shoulder surgeries. These strings are the closest thing to natural gut and I am now able to confidently hit shots that I wasn't before. Although some say that they are not great for spin generation, the 17 gauge with the open string pattern allow for fantastic spin generation close to what a polyester string allows but without the harshness stiff feeling to the arm. They are also extremely powerful and lively with the ball launching off the racquet yet with no sacrifice of control. Although a tad pricey, they are definitely worth the money for what you get. Great quality from a great established manufacturer of strings. The only disadvantage is the low durability approx. 6 to 8 hours of play yet this is where many polys deaden and lose tension and you have to restring regardless of whether the strings have broken or not.
From:Henry, 11/24/17

Comments: Unbelievable feel and great on the arm. I don't like poly due to my dense string pattern and low powered Prince Tour Pro 98. This string is very powerfull in my opinion. Had to change my strokes a little to make spin though which was surprising, but little spin is the only negative I have. It livened up my racquet. I recommend this for anyone wishing to liven up a racquet if you want a little power. Only have had them in for a few hours but seem to have no wear or tension loss. 5 stars!
From:Ty, 2/11/17

Comments: Good comfortable string with good feel. But since it is soft, you don't expect it to generate as much spin as a poly. The "problem" is its playability drops off after 5-6 hours of play if you hit hard. It is not breaking nor fraying yet but you begin to feel it is going dead. So it may not be much cheaper than gut, if you compare its usable life. Might be better as a hybrid on the crosses.
From:Mark, 11/15

Comments: I'd say the product description is very accurate -- this is a really nice, soft string with great pop and access to spin. However, it isn't much more durable than a typical multi. I am a hard-hitting 4.0 -- had shoulder surgery last summer and have been working my way back, now playing with a lighter racquet (Tecnifibre Tflash 300) strung at lower tension (50 lbs) to lower stress on my arm all around. I found this set up very comfortable and have been happy with how I've been hitting with it -- just wish the strings lasted longer. Not sure that there is a solution to that problem though! Definitely an excellent alternative to gut at a lower price point.
From:Dave, 7/15

Comments: Strung my RF97 with Biphase 17g on the mains at 59 lbs, Babolat RPM Blast 18g on the crosses. Great feel but for the hard hitters, the string lasted an average of 2.5 to 3 hours of play. Great for people seeking for good feel and playability.
From:Elton, 6/15

Comments: Using it on my second Prince 100 Tour (18x20) strung at 56 lbs. The other 100 Tour was strung with the X-one Biphase 18 (also at 56 lbs) which I wrote a short review on it's respective page. Similar to the 18, ball pocketing is great and spin is obtained more from techniques. The power level is a little less compared to the 18, which is expected. The feel and crisp however, is much less apparent in this 17. It is a good string no doubt. However, for me using the 100 Tour with flex rating below 58 and the feel everyone described as "mushy/soft/different" lack of crispness could be a deal breaker at this price point. There are many others multis that can give the similar results. If you are not a string breaker, I highly recommend the 18, else a firmer racquet may reap more benefits out of this 17.
From:GW, 2/15

Comments: Best hybrid I have used so far. Strung in a Wilson Pro Staff Six.One 90 on the mains at 51 lbs and Babolat RPM Blast 18g at 47 lbs on the cross. Good for the arm, great ball pop great overall playability. I observed a great loss in playbility if you use it on the cross due to significant loss of snap back. String set combination lasted 8 hours of play before the mains started showing signs of wear and dynamic tension starts dropping significantly. String broke after 12 hours of play. Now stinging my other racquets at different tensions to suit different conditions. Will be sticking to this product from here on end.
From:Elton, 1/15

Comments: I have been playing tennis for 30 years. I play from the baseline and hit topspin and play mostly on clay; I play indoor in the winter. Hybrid this with Luxilon Adrenaline in the mains and X-One in the crosses -- fantastic! The best of both worlds. I experimented with natural gut in the crosses but I'll go back to Biphase! My current string of choice.
From:Mishell, 11/14

Comments: I'm a 4.0-4.5 player who plays 3-4 times per week using a Head Graphene Instinct MP. If you play with topspin and pace this string gives you great feel and power. I cross it with Tourna Big Hitter 17 and string at 53 and I'm set. Used to play with Wilson NXT -- I'd consider it equivalent to that.
From:Shannon, 8/14

Comments: I recently purchased a stringer and a reel of this string for my 11 year old son. I cut out the RPM Blast to do a practice stringing in my Aeropro Drive with this string. I was amazed by how much I improved. My serve especially, kick, slice, or flat down the T out wide. I felt like a major league pitcher with a mastery of all the pitches. Net play is fantastic. If you are Nadal and need or want to hit 50 groundstrokes per rally from the baseline, this might not be the string for you. However if you are an all court player who is looking for variety, playability, and consistency? This is your string. Added benefit -- it is so easy on the arm.
From:Eric, 7/14

Comments: I'm nearing 60 (years not string tension) and playing singles three times a week at the 3.5-4.0 level. This is s great string for saving your arm and shoulder and living to fight another day. This string frays quickly but keeps its tension for a while before breaking. Although the 17 gauge is a bit less durable, it does provide more spin and control than the 16 gauge.. The string is a bit pricey, but it's a lot cheaper than physical therapy or surgery. I kept decreasing the tension until settling at 52 lbs in my arm-friendly ProKennex 7G.
From:Joe, 7/14

Comments: Using this in my Youtek Radical MP which is a low powered racquet. Strung at 57 lbs. I generate a slow to medium swing speed. I noticed a little more pop all around on my strokes. Felt really good on shoulder and arm after initial and subsequent hitting sessions. Good string.
From:JJ, 6/14

Comments: I used these strings back in 2008 for about 2 years, and I'd definitely recommend these for hybrid set ups. I would place a poly (usually Pro Hurricane Tour or ALU Rough) in the mains and the X-One Biphase's in the crosses at 57/59 lbs. It was my favorite set up because I'd be able to get spin from the textured poly, while additional comfort from the Biphase, even though it was strung that high. As far as a full frame of these strings, they played well up until they broke, which was about 3-4 weeks for me (playing about 10-15 hours per week, with a ton of spin). I'd definitely recommend this string for the gut-like feeling.
From:Kris, 6/14

Comments: I play with the Volkl Organix 8 (300g) and so far I've strung it with Prince Beast, Technifibre Black Code, Red Code, and RPM Blast. I strung this with a hybrid of BlackCode (52lbs) and Biphase (55 lbs) and it plays incredible. I do think the Prince Beast/Biphase combo might be better and I will try it next time. But, I will no longer be using VS Natural gut as my softer string with a poly after using this string! So soft and much crisper than natural gut!
From:Andrei, 9/13

Comments: I had this strung on a K 6.1 Tour leaded up at 55lbs. It plays quite well, the feeling was crisp, but not boardy, I had some ball cupping/pocketing, and it is very comfortable. Spin generation was adequate, I cannot comment on durability as I only did some drills, and played 2 sets of doubles. As usual, if you are a mega top spinner, durability will be a issue. I figure this could be good for people with arm/elbow/shoulder issue, or over 40 years of age (please don't be offended). It is cheaper to pay for string and labour, rather than seeing a doctor. My NTRP is a 5.0
From:Christopher, 7/13

Comments: These feel very good and feel soft, are easy on your arms and good if you do a lot of placement shots. I can stick with this string for a long time. But there is not that much power from the baseline and doesn't add that much spin and lastly, it don't last! It lasted maybe 2 weeks (approx. playing 8 hrs a week) and for me, that is a waste of money.
From:Jack, 5/13

Comments: After reading all the good things from all the reviews, I bought 4 of these X-One 17g. I must say that I'm a very good player, as I don't know how to rate it in number but I play tournaments and leagues in my country for years and with much success. Now, I'm telling you this because my feedback is very different from all I read. I strung it first on my Prestige IG MP at 52 lbs, and the racquet felt very stiff. I couldn't play with it normally, so then I cut it and made a new string job at 50 lbs. On the court again it felt stiff, and I couldn't find length, as balls went short or way out. This string killed my forehand (my main weapon), as I still couldn't find spin and power. So, I really suffer playing with it.
From:Ozi, 1/13

Comments: I have to say, it's a lot more expensive where I live, but it really is the bucks. It has the best feel I have ever had, and these strings last a long time! But that was when I used to hit flat so I don't know how this would put up with spin monsters. It's worth a try, and after using this string nothing feels better than this (except maybe natural gut, but I've never tried that either).
From:Ryan, 1/13

Comments: The best multi I can settle in. It's my summer string of choice. It plays great but won't last, as I broke one within an hour of a tough singles match recently. When I get tired of restringing I'd go Black Code, but when I feel like going back to multi the Biphase is always the one, even though I try others from time to time (pricing concern being the driver). I am a string breaker and string myself.
From:Dan, 12/12

Comments: I have been using this Tecnifibre X-One Biphase 17g as crosses with Signum Pro Plasma Hextreme 16L for a little over a month now. I definitely like the feel of both of these strings. The Tecnifibre strings have great feel and are soft, but fray like crazy. If you want a string that does not fray, these may not be your string. However, these play great.
From:D., 12/12

Comments: Very comfortable string with enough bite for control. However, I have never used a string that frayed and then broke so quickly. It's simply not economic. If you don't mind a restring every 10 sets or so then fine. Personally, although I string my own racquets it's not something I want to be doing that often.
From:Toby, 11/12

Comments: I am a soon to be 4.5 player who has been playing a Head LM Instinct strung with RIP Control string @ 57lbs ever since the racquet was released. Recently, I hit with a friend's racquet that was strung with X-One. I was so impressed with the feel and control that a week before the Nationals (Indian Wells), I strung my racquets with X-One and used it in the tournament. No regrets. Went 4 and 0, including, beating a great National Champion team from Puerto Rico 2/2 in doubles. High marks for X-One.
From:Anon, 11/12

Comments: This is a great multifilament string. Soft, firm, with good control, and some spin. This is very firm for hitting a regular forehand. It's the best multifilament for me now. I hope it has more durability. The price is a bit high. I strung a full bed at 53 lbs on a Pacific X-Force.
From:Tong, 8/12

Comments: This string is the perfect replacement for natural gut without the heavy price tag.It has "gut-like" feel with plenty of ball pocketing. I'm not a typical string breaker. I play 3to 4 times per week and have had this string for almost two months. I believe this is perfectfor my Wilson K-Factor Six.One 90 Tour (16x20) strung on the mains at 48lbs and the crosseswith Top Spin Cyber Flash at 44lbs.
From:Chan, 7/12

Comments: Great string, feels very close to Natural Gut. I strung thison my Head Youtek IG Speed MP 18x20. I loved this string on serve andfrom the baseline, gave very good pop. Control and feel was average,nothing special. What I found really annoying was the after 3 to 4 hoursof aggressive playing, the strings already began to fray. I used LuxilonALU Power 16L polyester strings before this and they lasted me a good 7to 9 weeks. The X1 Biphase breaks way to often and for it's price, it isnot worth it. I had it @54lbs tension. However for the 3 to 4 hours ofplay that I did have, they really preformed nicely, very elastic andpowerful. I got deep balls with power and good topspin 90% of the time.I recommend trying this string for its performance, however you'll needa deep pocket to afford it.
From:Bimal, 5/12

Comments: Great string, feels very close to Natural Gut. I strung thison my Head Youtek IG Speed MP 18x20. I loved this string on serve andfrom the baseline, gave very good pop. Control and feel was average,nothing special. What I found really annoying was the after 3 to 4 hoursof aggressive playing, the strings already began to fray. I used LuxilonALU Power 16L polyester strings before this and they lasted me a good 7to 9 weeks. The X1 Biphase breaks way to often and for it's price, it isnot worth it. I had it @54lbs tension. However for the 3 to 4 hours ofplay that I did have, they really preformed nicely, very elastic andpowerful. I got deep balls with power and good topspin 90% of the time.I recommend trying this string for its performance, however you'll needa deep pocket to afford it.
From:Bimal, 5/12

Comments: I used the X-One Biphase on my crosses and Kirschbaum Pro-Line II on my mains and it only lasted about 5 hours before it broke. I will say other than the lack of durability it felt great. I have some arm problems which this set up helped but it just didn't last long enough for me. I play with a lot of spin and hit fairly hard.
From:Joey, 4/12

Comments: String felt great and easy on the arm, but it started to fray after a couple hours and broke a couple more hours of hitting later. Once it frays, it doesn't have the spin or pop that it did. I strung it at 55 lbs.
From:James, 4/12

Comments: Really nice alternative to natural gut. I had a Dunlop 200 4D Tour racquet strung with the 16G version at 60 lbs and a newer racquet (same kind) strung with 17G version at 58 lbs. Both strings are very easy on the arm and offer crisp returns with good control. The 17G version has more power and better spin but less control than the 16G version as strung. Both strings move about (17G much more) and start fraying after about 2 months on but then seem to last for quite a while after that. Did not see much difference in durability between the 16G and 17G as both are shot after about 6 months (playing twice weekly). I play doubles (3.5-4.0 level).
From:Bert, 3/12

Comments: Very soft string and easy on the arm. I'm a 4.0 player and Iwas looking for an alternative to natural gut. This stuff did thetrick. It feels great from the baseline and on volleys. It frayswithin 2-3 weeks and then breaks shortly after that, so you will have toreplace often. For me, it's a fair trade-off since it's a good idea tostring often anyway if you play a lot.
From:jeff, 3/12

Comments: I was looking for a racquet to replace my Wilson K-Factor 6.1 95 18x20. I demo'd several racquets including the 2012 Babolat Pure Drive Roddick, Head Youtek IG Prestige MP, Boris Becker Delta Core Melbourne and the Wilson Juice Pro. The Slazenger Pro Braided tops them all. The open 16x18 string pattern gave me great access to top-spin and power. Ball control and placement was also top notch. Kick, slice and flat serves were all amazing. Where the racquet REALLY shines though, is at the net. The maneuverability of this racquet is almost telepathic. It's the perfect stick for the aggressive all-court or serve-n-volley player. This is truly an amazing no frills, get-the-job-done racquet! Definitely worth a demo for any 4.0+ player who likes it at the net!
From:Chike, 3/12

Comments: This is a great string. I love the feel, it plays crisp, it has a good amount of power. A big step up from the Wilson NXT Tour 17 I have used. A superb string. Strung myWilson BLX Blade 98 at 60lbs.
From:Rory, 2/12

Comments: Great string with a lot of feel and bite on the ball .. Better than the NXT Tour 17 that I have been using as it feels crisper but not tough on the arm .. Tradeoff? Don't expect it to last more than 12 hours as far as usable life is concerned.
From:Marv, 1/12

Comments: Very good in a full bed, but outrageously good in a hybrid. In a full bed, X1B 17 has many qualities of natural gut including power which is sometimes too much. However, when it is crossed with Black Code 17, it has all of the qualities I enjoy without the excess power thatcan cause balls to sail long. Try it strung at 58 with the BC crosses strung at 55 and let er rip. You will be amazed out how much power you can drive the ball with without losing your control.
From:Anon, 1/12

Comments: An excellent string for as long as it lasts, seems to fray then notch in less within 3 weeks then has to be replaced prior to breaking. I can't afford to use it.
From:Anon, 12/11

Comments: Advantages of the X1 string is that it has a soft feel to it. I can feel the ball well and it has spin potential and good pop. Disadvantages would be that it breaks easily, and I don't like entire string bed with X-One as it feels like a spring board. I also found it pricey. I like X-One in my crosses with Signum Pro Poly-Plasma on the mains and it works great. I went this route to get a little extra feel on the ball I felt I was missing with Signum Pro Poly-Plasma or Black code strung the entire way. X-One is not very durable so if you are a string breaker and don't string your own racquets I would not recommend unless you have very deep pockets. I am not what I would call a string breaker but I string 3 racquets at a time within 10 days rotating all racquets I will have to string at least one racquet again. I play around 3 days a week and am a 4.5 player.
From:David, 11/11

Comments: I agree with everyone else's reviews. This is an all around type string. I think it is similar to natural gut in terms of feel and touch.
From:Mikel, 10/11

Comments: This is an excellent string. There is tons of power, spin and control. But string starts to fray after first hour. Anyway, this string has become my string of choice. I use a Babolat Drive Z strung at 55 lbs.
From:Gennady, 10/11

Comments: I really love the Tecnifibre X-One Biphase 17 string. It's the best string I've used. I've recently been able to compare this string to NRG2 17. I have two Babolat AeroPro Cortex racquets; one is strung with NRG2 and the other with X-one Biphase 17. Both racquets are strung at 60 lbs. The X-one string is better in many ways. I don't hit with heavy topspin and only generate moderate racquet head speed, but I can definitely see that I have more spin potential with X-one. I also notice that the string gives more control and "effortless" power. I get better net clearance, good depth and I find it easier to move the ball around the court. It gives good feel at the net as well. Also, it's very arm friendly and I can hit with a lot more comfort. When hitting with NRG, I can feel a slight pain returning to my elbow. When comparing X-one Biphase 17 and NRG2 17, X-one is just a bit better in all categories. I play twice a week and the only thing that I don't like about X-One is its durability. Once it starts to fray, it looses some tension and the balls start to fly, a bit.
From:Glenn, 9/11

Comments: I love this string! It is very powerful and has a lot of comfort and feel. It has more comfort and feel than power. But they are all evenly spread out. I have a Head Youtek IG Speed MP 18x20 and I put these strings on it because I am trying out Novak's setup as an experiment. I even have his vibration dampener. These strings are great and I definitely recommend them. They play best around 57 lbs. Great string! But it lacks spin. It has a low spin potential.
From:Anon, 9/11

Comments: Great string! I was a gut user all my tennis life (30 years) and this string is close as I found yet. It is easy on arm and spin and power are there. I use it in my Head Prestige Pro 600 and it is a dream. 3.0-5.5 players can take advantage of the playability of this string.
From:Mark, 9/11

Comments: I have a hybrid of Tecnfibre X-One Biphase and Red Code 17 g at 26 Kg and while I love it, I have to say that it breaks way too quickly. X-One Biphase starts fraying in 3 hours and breaks in 4-5. The Red Code shows no signs of wear whatsoever. I just came back from tennis camp, played about 18 hours and broke strings on all my racquets. If you don't mind the constant purchasing/restringing than you'll love everything about this string, but for me, not durable enough.
From:Adi, 8/11

Comments: I suspect that of all the strings listed on this site with customer feedback attached, the X-One may have generated the most comments and with good reason; this is a very good string! I have a little variety in my game and whether I'm hitting with slice or top-spin from the baseline, making an approach shot or at the net, this string offers an amazing combination of power and control.
From:AJK, 7/11

Comments: This is a great string but expensive as it lasts about 20 hours of play. I am planning to buy a reel(660 feet) which may last me 12 to 16 months. Some stringers tell me that the reel will dry out in that time and I should buy a bulk order sealed packages of 40 feet. My question is: Will a reel last from 12 to 18 months without drying out? Or should I buy more than 10 sealed packages?
From:Ian. 6/11
(Ian, an X-One Biphase reel will not dry out. Gut strings would need to remain sealed, but this because X-One Biphase strings are made synthetic materials, they will last. -- TW Staff)

Comments: Great string. Provides good power, control, and spin. However, they will start to fray in 4 hours of game play and will break within 20. Highly recommended if money and restringing won't be a problem.
From:Jessie. 6/11

Comments: I have to quote the post below by Rich because I could not write it any better: "I was an advocate of the Tecnifibre NRG 17g line. Well after trying this string I am switching. This string provides noticeably more power, control,and spin. The wear has been acceptable. It's a slightly higher price but well worth it." I just could not agree more after stringing it up in my Organix 10 at 55/52.
From:Keith. 5/11

Comments: I haven't used Tecnifibre for 15+ years; their older products simply lost tension WAY too quickly for my liking, and I've always gone with Gamma or Wilson multis since then. My stringer recommended this product recently when I wanted to try something different, but my elbow simply can't handle poly for any significant length of time to use any of the myriad on new strings in that genre.This string was nothing like the Tecnifibre I remember from years past. This stuff is terrific: power, control, doesn't move around too much for a 17ga, it wears well, quite impressive indeed. I may have just found a new favorite brand of multi to play.
From:BL, MI, USA. 5/11

Comments: This 17 gauge string has good control, a crisp feel combined with just the right amount of power for my tennis style...full bed, no hybrid.�I depend a lot on control as my strokes are predominantly flat and deep on both sides (pretty much old school tennis Connors / Evert Lloyd style)...very seldom do I play with topspin. I really enjoy playing with this string in a Yonex Ultimum RD Ti 80 but found that it started fraying after about 6hrs of play.�These strings are still holding tension reasonably well but will snap anytime soon. I will be trying out the 16 gauge, which I'm sure will be more durable. Otherwise, I feel the durability to be a bit on the low side when compared to the price you pay.....but that's a choice I'll have to make real quick. This is definitely one of my favourite strings at the moment, but could be heavy on the pocket in the future. Would appreciate any feedback for similar strings that I could try out and might like that would suit my tennis style?
From:Glynn, Port Elizabeth, South Africa. 5/11
(Glynn, you might want to try HEAD FXP, Gamma Live Wire or Tecnifibre Multi-Feel to name a few. -- TW Staff)

Comments: I was an advocate of the Tecnifibre NRG 17g line. Well after trying this string I am switching. This string provides noticeably more power, control,and spin. The wear has been acceptable. It's a slightly higher price but well worth it.
From:Rich, Bethany Beach, DE, USA. 4/11
NTRP Rating: 4.5

Comments: Too crisp to be a real replacement for gut for me but it feels great to play with; good power and all spins are very easy to generate. Serves felt good, but control on groundstrokes for me wasn't as good as gut, power wasn't too bad either. Strung in a k factor tour 90 at 58lbs in the mains with pro hurricane in the crosses at 55lbs. Much easier to string than gut with none of the panic that accompanies it. Playing in damp or wet conditions doesn't seem to be as big a deal as when using gut either; in my part of the world I'd be stringing 3 times a week if I let my gut get wet and it's simply not practical nor is it financially possible. Gut is simply too expensive. If money was no object then I would be using 17g Babolat vs gut with the pro hurricane I use now, but until then, this will more than suffice.
From:Steven, Scotland, 03/11

Comments:Words cannot describe how great this string is! It's virtually a natural gut at the fraction of the price! I'm a hard hitting all court player so durability is an issue and I found that for a multifilament string it holds up quite nicely, it can last about twenty hours before I need to restring. It wasn't too cost effective as a full bed but once I strung it with the black code on the mains durability, feel, power, and spin were all there!
From:Earl, San Diego, CA, USA, 03/11

Comments: The best multifilament out there!! This string has a great balance of feel, spin, comfort, control and power. I quit using the NXT's and Babolat gut for this string. It's easy to string and the durability is good for a multifilament. I also appreciate it being easy on the body. If you like using a multifilament or gut...this is a must try!! Babolat Aero Pro Drive / Aero Pro Lite Mains 60 / Cross 57.
From:James, Tuscaloosa, AL, USA, 03/11

Comments: The best string I have ever played with. It really improved my weaknesses without harming what I was doing well with my prior string (Luxilon ALU Rough 125). Finally a string that doesn't make you have to compromise. My game simply got better! 4.0 Baseliner.
From:George, Boston, MA, USA, 02/11

Comments: Excellent string! At first I was a bit skeptical about switching from a poly to this multifilament string. To my surprise, it actually felt a lot better given the racquet I use. I found this racquet to have good power as well as control. This string also has more than average bite for a multi, producing good spin. The only downsides of this string is that on hot days the string can get a bit "mushy" and is not as crisp as a poly, but overall well worth the switch. 5.0 All around court player. Head Youtek prestige mp 53lbs.
From:Jaime, Mississauga, ON, Canada, 01/11

Comments: Go get this string and give it a try. Feels much much better than 16-gauge version (see my review in 16) and produces more spin because of its thin profile. What I like most about this string are its durability (I'm not crazy about topspin and I let my natural swing patter take care of it), power and FEEL. It is a joy to play with. It feels little stiff initially but you'll get used to it after couple of hours. You may actually want to tighten the string by 1 or 2 points as it's got lot of power potential.
After a year playing I started hybriding Lux Adreline 17 with x-one biphase 17. Lux compensates extra power Bi-Phase got and helps maintain Bi-Phase feel if not better. Totally arm friendly.
Happy hitting!
From:Bharath, Hillsborough, NJ, USA, 01/11

Comments: I cannot believe I have been using full polyester set ups this long. After trying this string, I really regret not trying them sooner. I hit the ball pretty flat and these strings were incredible. With minimal effort, I am able to generate amazing power. While there is some loss of control, the feel, comfort and power are worth it.
From:Barrett, KY, USA, 12/10

Comments: I used this to string up my Wilson Ncode Six.One 95 (18x20). The string feels very lively and does quite a good job at absorbing shock. I also like how my serves are coming off. I can't offer my say on durability since I have only been using it for one day, but I would recommend giving it a try.
From:Anon, 11/10

Comments: Strung on a Head LM Radical MP @ 57#. Soft feel, but not as soft as Gamma Pro 17, which IMO is a little too soft. I like the blend of soft feel and crisp response. Good power and spin as well. I am a topspin baseliner with a hard serve and I like the ability this string gives to hit out from the baseline, hit side spin dancers, or paint lines and corners as needed. Great all around string.
From:Dave, Jersey Shore, NJ, 4.5. 8/10

Comments: Has the best string feel ever next to gut. I put it @ 60lbs on Wilson BLX tour 90, the feel and precision of the shots were amazing. Touch is exceptional, especially on defensive lobs, slices, and drop volleys. When I am stretched out by wide shots, I can confidently put the ball back in the court. I had Luxilon Alu Rough in the racquet before, the feel was horrible, this string is so much nicer (I�ve used other polys and I liked them, except the Alu Rough). Durability isn't a big problem for me cause I hit most shots flat or with moderate spin, after 3 sessions no signs of fraying at all, and tension is holding up well. Only downside I discovered is control on forehand side. When I was using polys, the low power and extra spin keeps those forehand line-kissers, but with this string, I have to hold back a bit when hitting forehand or try to add extra spin on the shots. Overall 9.5/10 rating, my favorite string other than Babolat VS natural.
From:Yang, Berkeley, CA, USA, 07/10

Comments: Best string I have EVER used. The only problem is, is that its way too expensive and I break them in about 20 mins, basically in the warm-up. So if they weren�t so expensive I would string them up regularly so if you can afford them get them.
From:Josh, NY, USA, 05/10

Comments: X-One Biphase 17 is a great string. I strung it @ 63 lbs in my Liquidmetal Radical OS. It felt very comfortable regardless of my high tension and fairly tight 18x19 string pattern. It moves quite a bit but that's harmless :o) Two thumbs up!
From:Anon. 5/10

Comments: It continues to change its tension and response over the days. Has lost much pop. I have to give this string thumbs down. I much prefer Wilson NXT or Gamma Asterisk over this string for a multifilament.
From:Nori, Queens, NY, USA. 5/10

Comments: I'm an aggressive 5.0 baseliner with big serve and forehand. I used this string as the cross in a hybrid with Babolat RPM Blast (16G). Al I can say is WOW! If you are looking for a much cheaper alternative to gut this is it! When you take the string out of the package it has a gut like feel to it, but much easier to string as it does not fray or slip like gut does when you clamp it. When combined with a high performance polyester string that gives you access to spin and power this string will balance out the hybrid blend to provide excellent comfort and feel the poly cannot. I bet if this string was used for the entire frame it would perform very close to gut but it would probably have poor durability so you should use it in a hybrid if you are going the economic route.
From:Anon. 05/10

Comments:update: Actually, the strings loosed up over the last few days to a good tension (was 55lbs); maybe not good if you are pro playing with fresh racquets. It's fairly stretchy/'rubberband-y', with a good amount of 'give', but only to a certain extent and is still fairly firm. Some compared it to gut, but I think the response is quite different in character and definitely feels 'synthetic'; again I would compare it to Gamma Live Wire Pro.
From:Nori, NY, USA, 05/10

Comments: It's true what another person said; I strung my Pure Storm Tour (98 sq in) at 55 lbs, and it feels more like 60-62 lbs. I was shocked; The string bed feels very firm. Shots made in the center feel crisp and fairly good (like Live Wire Pro), but shots made even little off center are fairly jarring. Not a huge fan at this tension. I will try a lower tension if I ever try it again. Correct tension is probably like 50 lbs on this racquet. Think I still like Wilson NXT 17 or Gamma Asterisk 17 better; but maybe I would think different if I had the correct tension; who knows.
From:Nori, Queens, NY, USA. 5/10

Comments: The string is amazing. Feel, power and spin, It's all in there! BUT! It has poor durability. I play varsity for my high school team, practice 5 days a week and matches 3 times a week. I strung it at 58 lbs, and after a week and a half, the string starts shredding. It popped 2 days go.
From:Dex, Pburg, NJ, U.S.A. 5/10

Comments: A great string -- power, control, touch, spin, it's all there. I use 17 gauge at 55 pounds in an Aerogel 300 4D.
From:John, Charleston, SC. 5/10

Comments: I really like this string and prefer it over any Wilson NXT or Babolat Xcel which IMO are overpriced! This string performs very close to gut and hold tension well too. I would not hybrid this- especially with Luxilon, full string 57- 62 lb .
From:M.Darius, Bethesda, MD, USA. 4/10

Comments: This is the BEST STRING ON THE MARKET! PERIOD! You will not be disappointed in this string. It offers excellent control, feel, power when you need it, and I was very surprised at the amount of spin it generates! WOW! However, you must string it 5 to 6lbs LESS than you normally would string your racquet. I don't know why, but after I had my Volkl power bridge mid10 strung at 58lbs. It felt like 63lbs! I thought my stringer strung it wrong, so I had it re-strung again; SAME PROBLEM! So I strung it way low like pro player Marcos Bagdatis at 50lbs. Mains and 46lbs. at crosses. WOW! There's so much more power and control. This set-up feels like 58lbs to me. This string is so good specially for the price, it lasts very long too! Amazing! Best string on the market.
From:Will, CA, USA. 03/10

Comments: Tecnifibre X-One feels and plays like gut at a fraction of the cost. Doesn't last long enough for a full set, but I strung these as the cross with MSV focus hex in the main and it is the best hybrid set I have ever played with. You get the spin and control of the MSV with the power and feel of the X-One. If I could afford to restring after each session, I would go all X-One, but this is the best alternative for the average player.
From:Shaun, Maui, HI, USA, 02/10

Comments: I've been using these as a cross-string for months in my PD Roddick GT @ 58lbs with LLBB in the mains, but have decided I prefer them as the full-bed. Great power, comfort and a surprising amount of spin for a multi. Yes, they don't last long, but for those with their own stringer, they are worth it. Best feel out there of any non-gut in my opinion.
From:Darin, Richland, WA, USA, 01/10

Comments: Bought for my daughter who plays varsity in high school and strings her own racquets. These strings are expensive but the control/comfort/spin are almost worth it. They were not as durable as I hoped, lasting only 7 days (2 hours per days on the courts). My daughter hits with above average topspin. We are looking for something that plays as well and is more durable though.
From:Anon., 10/09

Comments: This has been my favorite string I have used. I play a Yonex RDS 003 and feel so much more confident about my game. Can't wait to start to tweak the tensions and see what else I can get out of these bad boys.
From:Matt, Missouri, USA. 10/09

Comments: Agreed, don't pay attention to the negative comments. People need to pay more attention to the construction of a string and compare it to similar strings. This string seems to work best in mid-size frames that are on the stiffer side like a Wilson Pro Staff 6.1 classic because it opens up the pattern a little more. The string is best comparable to other multi fils like Wilson NXT and NGR. Personally I'll take this string over NXT because its a little firmer feel on ground strokes but also has softer touch on more delicate shots as well as good ball pocketing without TOO SOFT a feel.
From:Joe 4.5, Woodstock, Georgia USA 08/09

Comments: Switched to an all X- one biphase from a hybrid of Big Banger and Xone.The spin is incredible and so is the power. Felt that Big banger dampened the racquet and added nothing to my game. This string brought my racquet to life. It does not last as long as the hybrid, but whats important- winning matches or string cost?
From:HD, Abudhabi, UAE 08/09

Comments: It feels like this string grabs the ball and throws it over the net. It is immediately noticeable. I was surprised at the amount of work I got on an American twist serve. Extremely crisp. I will have to wait to see if it is elbow friendly, like the TGV.
From:John, Atlanta, GA, USA. 07/09

Comments: Don't pay attention to the negative reviews. I decided to try the Tecnifibre X-One Biphase 17 string red. From the start a big, big difference. Immediately, I felt the advantages of using this strings. Better feel, better control, more topspin, more power & spin on your serves, holds the tension well & at the same time soft on your arm. Actually, with these new strings, my new racquet became alive. The only thing I didn't like is the durability. I have been playing with the same strings for about three weeks now, but by the way they look, it seems that they only have one to two weeks more to go. So I decided to put on string savers on my next Tecnifibre X-One Biphase 17 string red that I have already bought for my new string job. Go ahead & try this strings, you won't be disappointed by the overall performance & actually it may improve the level of your game.
From:Luis, Edmonton, AB, Canada.

Comments: This string is very GOOD as a hybrid, you just have to use the right poly on the mains otherwise it crashes fast. I used a poly string as a hybrid and almost every shot I hit went in..you'll have to figure out the combination can't let the secret out!
From:Janae, USA. 04/09

Comments: Great feel, power, comfort, durability, everything. My current string and it plays pretty darn well. Strung it of my Kfactor KSix-One Tour 90 at 55lbs.
From:Jason, Va, USA. 2/09

Comments:This is my first experience with Tecnifibre (after reading about it on TW, had to try it out). Strung on my Prince and Wilson rackets, both in hybrid setup: Tecnifibre X-One 17g (57lb) main with poly strings 17g (54lb) cross. Played on outdoor public courts, it's very cold. The X-One made the setup playable, good power, top spin and slice, good bite. Been playing for 2 months now, no signs of wear, no shredding, yes, the strings are moving now on my Prince racket, but no movement on my Wilson Kfactor. Is X-One available in a reel? I'm going to try more Tecnifibre strings in my hybrid setup now.
From:Jami, Walnut Creek, CA, 12/08

Comments: String doesn't last if you hybrid with Luxilon Rough. lasted like a week or so.
From:mathew, California, US. 11/08

Comments: An amazing string. Exceptional, with unsurpassed power. Control is outstanding despite all that power and pop. The consistency from shot to shot is really commendable. However, I think quite different from other reviewers. It is not as comfortable as other quality strings. NRG2, 515 are clearly more comfortable. They're more gummy. X-One is wiry, stiff playing. This also affects feel/touch. Again, compared to NRG2 and 515, the touch is just not there. Not a very good string for aggressive net play (basic volleys are good though). Strings don't move much, even though i'm taking really big cuts at the ball. Tension retention is not as good as NRG2 or 515. Again this is understandable, considering the power characteristics. Price is good. I tried VS Team 17 and X-One 17 blows it out of the water in terms of power and control. Spin is quite good as well, much better than VS but only almost as good as 515 and then NRG2. I'd say this is the best string for an aggressive baseliner, who occasionally goes in for a volley putaway or a smash. It isn't very suitable for a serve and volley game, the touch and feel are insufficient. I'd probably say that NRG2 17 is the best overall string on the market. If you simply want power along with very high control, X-One may be the best there is, even better than many guts..who knows.I used it on a Volkl C-10 Pro Tour (93, 353 grams, 61 flex) @ ~58-59 lbs. Used it for 1.5 months exclusively, playing almost everyday; no breakage, not much fraying. Only in the last week it lost more tension and started feeling a bit subdued. Might buy again and install it as a cross, with gut on the mains. I think I'll have the best power, control, tension retention, touch, comfort combination available on the market then.
From:Memed, Istanbul, Turkey. 11/08

Comments: This string feels great in my Tecnifibre T-Fight 295. I have been experimenting with lots of hybrid combinations and I stumbled upon an interesting, long lasting set-up. I put this Biphase 17 in the crosses and Gamma Asterisk 17 in the mains-both multi-filament strings. Seriously, I've had these strings in for almost a month and the sweet spot is still very responsive, yet forgiving at the same time. I'm 27, hit the ball pretty hard and with lots of topspin, the Gamma in the mains doesn't even have notches in them yet; weird. Usually I have the racket on my stringer by now for a new set, but they just won't wear out. It's like one of the packages is marked wrong and I really have polyester strings in! The Gamma is a good string, but I will go back to my favorite Klip Venom in the mains to compare again. I love stringing and experimenting with all the cool tennis stuff out there; I've had the bug for over a year now and would recommend to anyone who enjoys the technical side of sports to buy a stringer, it's easy and pays for itself in the long run.
From:Joplin, Missing Monterey Bay, USA. 11/08

Comments: The best multi string out on the market. It's amazing how much power I got out of it and the durability is exceptional. It lasted me three months and is now showing slight signs of wear.
From:Rasheeq, USA. 9/08

Comments: This string is simply the best synthetic on the market today. It has the feel of natural gut, but with a little more power and durability.
From:John, Suitland, Maryland, USA. 8/08

Comments: Ok here is the deal, I use Tecnifibre X-One Biphase 17 string as a hybrid with Babolat Pro Hurricane Tour 16, and I have to say that it's simply amazing. Every shot in my arsenal feels crisp thanks to the Tecnifibre strings as crosses and I can notice how much spin I get with the Babolat Pro Hurricane Tour. The only thing that I notice is that because I am a big hitter that the Tecnifibre strings are starting to fray a little bit.
From:Tyler, WA, USA. 8/08

Comments: I normally use a hybrid Luxilon Alu Rough with Wilson NXT crosses, but I tried out a full set of the X-One 17s while I was waiting for a new order of strings to arrive. The X-One offered great feel and decent spin, but it wasn't as powerful as my normal setup. I'll consider trying them out as crosses with a slightly lower tension. Babolat AeroPro Drive, X-One 17 @ 61 lbs.
From:James, Emeryville, CA, USA. 7/08

Comments: Great string. String it in the mains, with Kirschbaum Pro Line II in the crosses. I'm still experimenting with tensions, but I believe this will be my permanent set up. Nice power feel & comfort. Currently at 58/52 in a Yonex RQS 22. I am a 3.0 senior all courter.
From:Stewart, Decatur, GA, USA. 7/08

Comments: I only read the description of this (and many other) strings without reading any feedback. I ordered it on a whim and told them to string it a little more toward the power end. From the first time I played with this string, I felt I had a larger sweet spot, I had more "feel" than with any other string- spin, power, AND control were all there. My league members even remarked how well I was playing. I've never been happier with any other string- ever! Highly recommended!
From:Lindsay, Oklahoma City, OK, USA. 7/08

Comments: I have tried a variety of multis during the past couple of years as well as some multi/co-poly hybrids, and I keep coming back to this string. For me, they're the best non-gut synthetic. I get no additional spin, control and power from a poly than I do playing X-One. My only "complaints" and the reasons why I've experimented with other strings, are durability and the strings move around a lot. But, because it does everything else so well, I'll continue to use this string as long as Tecnifibre makes it. My set-up is a Babolat Pure Storm Tour at 56 lbs all around. I've used the red X-One before in this racquet, and it looks really nice.
From:Adam, Southern California, USA. 3/08

Comments: This was the worst string I have ever used in my life. Every ball that I hit felt dead, and every time I tried to hit topspin, the ball went dead on me. If I were you I would not pick this string.
From:Anh, Spring Lake Park, Minnesota. 3/08

Comments: I used this as a cross string with Luxilon in the mains. It felt great, but it was totally trashed and broke after a only a few hours.
From:Matt, Chicago. 2/08

Comments: Great string, but fairly bad durability.
From:Andrew, Ringgold, GA, USA. 2/08

Comments: The strings were great; I got a lot of pop and control.
From:Mike, CA, LA, USA, 11/07

Comments: Compared to the new Wilson K Gut Pro, this string is fantastic. Both have a tacky feel when freshly strung. Nothing I've tried surpasses the soft, playable feel of X-One Biphase. The more expensive K-gut Pro is crisp, but the soft controlled feel of X-one is superior. I have 16-gauge X-One on my 18X20 Tecnifibre 320. I found no durability issues using the thicker gauge, but I used 17G on my Liquidmetal Rave mains with ALU Rough 16L on the crosses. Great for a 16x19 stringbed for power and control if you don't mind the softer mains being cut by the stiffer poly crosses. I don't know how a hybrid bed would work with the X-One strings unless you use in the crosses. They are very soft and don't hold up in humidity or moist conditions (like gut).X-One Biphase compares favorably with playable Gamma strings like Live Wire 17 and Gamma Professional. All of these strings suffer in durability if you hit with heavy spin. Fraying is evident after just one play with 17 gauge versions. If you're a string breaker, I recommend 16G X-One over all other brands. If you desire the extra feel from 17G, well the Tecnifibre X-one Biphase strings are worth the price at 75% the cost of Gamma Professional or K Gut Pro.
From:Jim, Montgomery, TX, USA. 10/07
NTRP: 3.5

Comments: I love the way the ball feels when I hit using this string. I believe it is perfect for my Wilson nTour 95sq (16x20) strung at 60lbs. I've noticed much more spin on my shots and the part I love the most is the way volley's go where I direct/want them to go like I've never experienced before. It also provides nice power and control blend in this low-medium powered racquet. I've also noticed that I have more control on my lobs when opponents approach the net. I highly recommend this to any player looking for great feel, control, desire for topspin, and laser feel on volleys. I am a 3.5 player comfortable enough at the net, but working toward being an all court player.
From:Mike, Arlington, VA, USA, 09/07

Comments: Every now and then I get this great idea that I should try another string. I catch myself reading reviews or comments and get curious. But every time I go back to Tecnifibre X-One Biphase...I wonder why I strayed away. X-One hits with the right combination of feel, control, power and consistency for me. Some people say it goes dead after a short amount of time. To me it plays better and better right up to the breaking point. Only thing I have against the string is that it plays a little stiff the first hour or two. Gamma Professional is the only string I have played with that might play a bit better...but considering the cost, I'll stay with X-one.
From:Rondall, Glen Burnie, MD, USA. 8/07

Comments:Only problem with this string is that it isn't sold in a half set. Have to buy a whole set when using a hybrid. I like the power and pop with this string but with an 18x20 string pattern I could not generate much spin. I would recommend this as a good cross with Babolat hurricane or Wilson Enduro in the mains. This string also starts to fray within 2 hours of play.
From:Dave, Lajolla, CA, USA, 08/07

Comments: I tried this because of all the good feedback that there was, before this I had been using the HEAD FXP POWER 17, this string had much more control, and somewhat more spin. Overall I would recommend this string.
From:Vincent, USA, 06/07

Comments: These are the best strings ever. I play with Ashaway Kevlar 17 gauge tension 57 on mains and changed from synthetic gut to Tecnifiber x-one gauge 17 on crosses. The spin, control, and power at tension 61 on head liquidmetal radical are just amazing. This is the best string in the world right now. Period. No arguments.
From:Hormaz, Saipan, Northern Mariana Islands, 04/07

Comments: I tried these strings with some new Volkl V1 DNX frames. The 17-gauge string or the frame really triggered some very severe tennis elbow. I have always used Tecnifibre strings in the past and used the NRG2 16 gauge with great success. It's been a year and after taking 6 months off my elbow is back to normal. I am going to go back to the NRG2 with the same frame that caused the elbow problems and see if the elbow holds up.
From:John, Temecula, CA, USA, 03/07

Comments: Great string. I love it so much. The only thing I didn�t like is the durability. So I decided to put on string savers and try the 16. Must try.
From:Anon, 12/06

Comments: Without a doubt the best synthetic string on the market (and better than some natural gut). I'm a racquet stringer and use to recommend Wilson NXT 17 to my serious playing customers. In the last year from my recommendation they're all playing with Tecnifibre x-one Biphase 17 now and everybody's happy.
From:John, USA. 11/06

Comments: Probably the best string I�ve used this far along with the Gamma TNT Fusion 19g. Initial feel was okay but after a few hours of hitting it felt great. The only problem with this string was that it didn't last me very long so I don't think I�ll use it again due to the price. And just a random bit of info, the strings broke on the crosses for me.
From:Lawrence, Placentia, CA 08/06

Comments: This is by far the best, most "gut-like" string I�ve ever played with. I played with BDE gut Rally and was happy. In the past I have also tried many that claim "gut-like" feel like Gamma Pro XP, Laserfiber Pro, etc...but nothing seems to come close. I would say that this string even felt better than my favorite natural gut as far as feel, control and power. I hybrid with Luxilon TI-MO as I did in my gut string. Tecnifibre X-One Biphase 17 String just feels better and my control is now awesome.
From:KC, California, USA 07/05

Comments: The best multifilament around for the first 15-20 hours, after which the string becomes slow to react and I feel like I need to push the ball off the strings in mid-stroke. I play a ProStaff 5.0 at 62lbs. Strings typically do not break until about a 30-40 hours and when it does it�s always a cross.
From: Nekki, Los Angeles, CA, USA. 04/05

Comments: Great string. More control than NRG2 and better feel. Better than gut in that you don�t have to worry about the damp. This string is easier to string than gut. Great string. The best multi out there for feel, great job Tecnifibre.
From: Bill, Alberta, Canada. 10/04

Comments: This string offers great feel, power and control. At half the price of gut with similar characteristics-it's a great buy. String durability suffers with the thinner gauge lasting about a month before fraying. I'm an all court 5.5 player who strings his Head Mid-plus XL i.Prestige between 56 and 62lbs.
From: Damion, Los Angeles, CA, USA. 08/04

Comments: The 16g version is just as good. I would say that the string is stiff/ yet soft when you hit hard. Strings do lock in place. Durability is extremely better than Tecnifibre NRG2. I play two times per week and have had this string for almost two months. I'm almost tempted to say that it�s worth the price.
From: mackadilly, Talk Tennis. 4/04

Comments: I thought this string was really nice. Gummy like the original Tecnifibre 515, so the strings locked in place, responsive, powerful enough, great soft feel, big sweetspot, great spin. Suspect the durability might be better than Tecnifibre NRG2, especially since the strings aren�t sliding around at my usual tension. Tension maintenance appears to be much better. I did a pre-stretch when stringing.
From: NoBadMojo, aka Ameliaislanded, Talk Tennis. 4/04