Comments: This string has been great for me. I've had it strung in my Babolat PD 107 for a couple of months already. I don't know how some of you break it in hours? I'm no pro, but I don't hit soft dinky shots all day either. Playing 6 to 8 hours a week, 3 days, doubles. It has good power when I need it, good touch, and durability. What else could one want? Highly recommended!
From: B.D.P., 10/12

Comments: I used to use Babolat RPM Blast at 45lbs on my Aero Pro Drive GT. After about 4 months I could not take it anymore. I loved the string but I love my elbow more. I switched to Technifibre X-One and my tennis elbow has healed remarkably well. I love the X-One. It's plush with good power and spin. I have actually improved my game with this string. I string it at 50lbs. The down side is the life span. It starts freying after about 2-3 hours of play. For me luckily cost is not a real issue, it's just the hassle of stringing often. But on a more positive note it means I get to use fresh strings often. But to be honest, the X- One has probably saved my elbow and the numerous physio bills I was going to have to pay to play!
From: Eric, 9/12

Comments: Perfect string when it is freshly strung. But breaks in less than 4 hours (max) even if you are not a hard hitter. And at that frequency (and price), you may as well string it with a good 16 gauge gut which should definitely last longer. Otherwise great string if you can afford it and/or if your stringer lives next to you.
From: Marv, 5/12

Comments: I just tried this in one of my Wilson K-Tour 95s and am pretty impressed so far! I had been using Wilson NXT Tour 17 so it's not a quantum leap up from what I'd had (still do in other 2 frames) but noticeably superior string! I had a little trouble consistently bringing 1st serves down but it was 1st time I'd used it so probably just need some reps with a hopper to adjust (or may have just had an off serving day). Basically it's like NXT (which I've used for 2 1/2 years), only better! Tecnifibre definitely impressed me on our 1st outing.
From: Sid, 11/11

Comments: I had this X-One Biphase strung as a main with poly in the cross at 57 lbs on both. Wow, is all I can say about the feel of X-One in the mains. Feels almost like natural gut. Only thing I didn't like was that the X-One broke with only 4 hours of play. Broke right in the middle when I was going for a flat powerful forehand winner and it worked. Definitely worth the money.
From: Serge, 8/11

Comments: Really really enjoy playing with this string. Strung up at 65lbs in my Babolat Pure Storm ltd and even at that high of tension still plenty of power coming off the stringbed. Only complaint is that the strings move more than any I have ever used. Overall, though, a great string.
From: Luke. 6/11

Comments: I was previously using the Gamma Professional 18g on my Wilson Six-One BLX Tour and tried this. However, it has very little bite compared to the Gamma Pro - the Gamma gives me a lot more topspin.
From: Ken, Carlsbad, CA, USA. 4/11

Comments: I've tried several strings but I keep going back to these. The only thing that tops it is VS Team but that is insanely expensive. I've tried Lux Ace, VS Team gut, Alu power, Blackcode, RPM blast, Live Wire professional, Xcel Premium, NXT Tour and Pro Hurricane. Easily the best overall string I've used and incredibly arm friendly. Best characteristics are feel, touch, control and comfort. My 2nd favourite is Luxilon Ace 18 but being a poly, it isn't as friendly to the arm as a multi. Good combo if you have it with a very soft racquet.
From: Dave, Sydney, NSW, Australia, 03/11

Comments: This is my favorite string. I played all last summer with RPM Blast (17 ga) and it killed my arm. I tried Babolat VS (17 ga) and it was good. X1 BiPhase 18 ga is better than them all! It is a very soft string, but bites the ball generate a ton of spin. I hit the ball pretty flat, but the topspin jumps off the court when the strings are new. This string is also easy on the arm and generates a bunch of power on serves.
From: David, Weston, CT, USA, 12/10
String type and tension: Tecnifibre X1 Bi-Phase 18 ga. at 56 lbs.
Dunlop Aerogel 300 (16x19)

Comments: Put this string on my AeroPro Drive Cortex Plus at 59lbs. So far I really like this string, easy on my elbow, control and power are good. My second serve has quite a bit more slice to it than with other strings I've used in the past. It will take a few more weeks to determine the durability, but it not touted as a string for heavy top spin hitters. I can generate plenty of power with this string without having to come out of my shoes.
From: WES, Toledo, Oh, USA. 4/10

Comments: Here's the story; I put this on a Pure Drive GT @53lbs; I like the feeling, very comfortable, good control, spin. Honestly it felt close to a natural gut for me. I'm having a wrist issue; but when I played with this string, I barely felt the pain. The only issue that I had with this string was the durability; it broke after over 2 hours play. I'm going to try the 17g with the same colour (natural), FYI my other racquet is using 17g red and in my opinion it's a bit stiffer than this. I reckon the colour makes a difference in stiffness.
From: Makoto, Sydney, AU. 4/10

Comments: Strung this in the mains of my K6.1 Tour at 48lbs with Luxilon Supersense in the crosses at 43lbs. Feels awesome, tons of cushioning with completely unexpected access to lots of topspin. Loads of control, you just need to hit smoothly and use the ball pocketing to your advantage. Slices took a bit of adjustment as the ball would stay on the strings longer so that you end up framing it as you slide the ball across the string bed from the sweetspot all the way to the frame. After adjusting, slices when hit right are wicked, the ball just skids through with no bounce. Makes it so much easier to play with, I automatically started to play smoother and more relaxed. I was able to generate awesome power just by hitting smoothly. Stretched out wide shots become easy as you don't have to muscle the ball to get enough momentum to hit a shot back with decent pace and spin. Only downside is durability, even at my low tension it only lasted about 6 hours, I broke the string along 5 mains on a serve lol!
From: Converted, UK, 02/10

Comments: I've been playing with Bi-phase 17g for the past 3 years and I finally got around to playing with the 18g. Very nice control and easier access to spin. There is also an incremental power drop in groundies, but for my doubles game that's less of an issue. I strung my Aerogel 200G at 2 lbs lower (61 lbs) compared to than what I normally string the 17g Biphase.
From: Kevin, San Jose, CA. 3/09

Comments: I strung this on my kblade 98 at 53lbs. It has great feel and power. Also a good string if you have elbow problems. Out of all the strings I have tried I would either recommend Luxilon Big banger alu power or Tecnifibre x-one. For more durability get the string in 16g or 17g. I have just ordered a whole load of things yesterday and I brought a lot more of these in 17g.
From: Anon, Auckland, New Zealand, 11/08

Comments: This string is pretty good and plays best when played in for a few hours, however it won't last you more then a couple of weeks max (about a week playing every other day for me. Strings move about fairly soon after stringing and fraying occurs noticeably within 2-3 hours of play. Its nice enough but nothing exceptional, I will be looking for an alternative. Strung @ 56lbs in a Dunlop Aerogel 200.
From: Jon, England. 4/07

Comments: I tried this at 58lbs cross with poly power 19 gauge as main. Lots of power, a little crisp, no durability (6 hours), and soft on arm. Even as a cross string, it is not durable. Excellent on serves. Good pocketing when used with poly as cross. I like it very much, however, I have my own stringing machine. Still recommend it for those who enjoy good strings but willing to pay. I hope that Tennis Warehouse convinces the company to drop the price down. I enjoy tennis and enjoyed the string.
From: Peter, Vancouver, BC, Canada, 02/07

Comments: Strung the X-1 Biphase 18g in the mains with Gosen SM 18g in the crosses in my Babolat Pure Storm (modified to 12.2 oz). I love the softness of the Tecnifibre with the crispness of the Gosen. This string feels close to natural gut in terms of feel, ball dwell time/pocketing. Highly recommended.
From: Marc, Roswell, GA, USA 08/06

Comments:I put this in a Head liquidmetal Radical Midplus racket at 63lbs. The first time I strung with it, the string broke on the final string. I haven't broken a string while stringing in over two years, so you can imagine I was slightly upset, especially since it was the final string. However, I restrung the racket, and I must say this is a very crisp, soft feeling string. I look forward to playing with this on a warmer day, as it was low 40's when I hit. I have been longing for a 18g string for the Radical's tight string bed, and this felt really nice!
From: Frank
Dallas, Tx, USA 12/05

Comments: I put this in my RDX-500 HD at 60lbs and it's been fantastic. At first it was a bit stiff feeling but after a couple hours it was like the ball was just hanging in the string bed waiting for me to tell it where to go. Great spin and power, holds its tension very well...I've had it in the racket for over three weeks now, have played over a dozen matches with it, and it's playing better than ever. I wouldn't recommend the 18ga for an open pattern, but for the High Density Yonex it's exactly what I was looking for.
From: Darrel, Yelm, WA, USA. 9/05