Tecnifibre X-One Biphase 16 String Red
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A premium multifilament string, X-One BiPhase delivers superb comfort, feel and a crisp response. A good choice for players seeking an arm-friendly string without sacrificing power. Provides good tension maintenance too.

According to Tecnifibre, "the X-One Biphase string uses High Heat Capacity (H2C) fibers which allows the use of an innovative chemical treatment process called Trimerization. This new process increases the cohesion between chemical molecule links through extreme variations in temperature to result in ultimate dynamic efficiency (power) and exceptional feel. The new patented Biphasic process, with its visible marks on the string, extends string life by 20% and offers increased spin. Similar to its leading string, NRG2, the multifilament fibers within this string are immersed in polyurethane to provide shock absorption and optimum comfort."

  • Gauge: 16 / 1.30 mm
  • Length: 40 ft / 12.2 m
  • Construction: Multifilament / Polyurethane / H2C fibers / Biphasic treatment
  • Color: Red
Learning Center

Comments: I used the X-One Biphase 16 Gauge string in a Yonex VCORE 330 strung at 50 lbs. I found the string comfortable and it provided a lot of power on flat serves and good spin on my second serves. Unfortunately, the string snapped after two hours because I miss hit an overhead at the very top of the frame. I will try it again and I'm sure it would normally last 20 plus hours.
From: Jay, 3/15

Comments: Buyer beware, this string will hurt your elbow and your arm. When originally shopping for this string, I understood from the reviews that it would be a softer string that was easy on the arm. It is stiff as a board and unforgiving. I tried it on three racquets, and each time successively lowered the tension, thinking I could find a tension that would make it playable - nothing worked. No bite on the ball, stiff as a board. To note, the strings I purchased were the red ones, as I read the posts below, I see someone else who had quality problems with the red strings.
From: David, 3/13

Comments: I really liked this string for the 2 hours that it lasted. It was very lively and the feedback was good. I normally do not break strings and I didn't expect this one would break so fast. It was professionally strung, so I doubt it was a bad stringing job. I might have ran into a bad batch or something. Strung it at 59 lb on Dunlop Aerogel 4D 200. Would use it again, but can't justify the price to try it one more time.
From: Gru, 3/13

Comments: I've been using this string for close to 7 years now and I wouldn't use anything else. It's combination of power and fell is unrivaled and if you are an intermediate to aggressive player, adding these strings to your frame is the easiest way to take your game to the next level. I would not recommend this product if you are someone who does not like to break stings, as the overall durability isn't the greatest. One set of strings will usually last 8 to 10 hours of heavy hitting before giving in, but in that time there is almost no noticeable loss of playability.
From: Steven, 2/12

Comments: This string has great feel and pop, and doesn't slide around. My favorite string yet.
From: Anon, 12/11

Comments: I used these strings in the mains with Signum Pro Plasma HEXtreme in the crosses. I broke two mains within one and a half hours. Otherwise, the string was nice and soft on the arm. Stringing it was nice and easy, as it was quite a flexible string. My only complaints are that I feel that it was a bit mushy and I lost the ball in the stringbed a little. Great string, but I wish that it was a bit more durable.
From: Alex, 12/11

Comments: Response to Steve, 8/11, below and others experiencing short string life, Steve mentioned the problem with the crosses wearing prematurely, I experienced the same problem. The solution is to reduce the tensions of the crosses to the mains. Not easy and you will need several trials, but if you stick with the mains at a set tension, reduce the crosses until you no longer see the wear or at least see equal wear on both. For me, it was 62 mains, 58 crosses. Every racquet head is geometrically different, so it will be trial and error for different rackets and users with different tensions.
From: Tony, 10/11

Comments: I tried this string in a Wilson K Blade Tour after being a loyal Wilson NXT user. I prefer this string to NXT and I really liked the NXT. This string is very arm friendly like NXT but has a little more punch or feels a little more crisp. The string surface allows for some nice spin as well. I'm sold on this stuff!
From: David. 08/11

Comments: We kept X-One in the mains and put a "Poly" in the crosses and that works great! The mains still look new after a week of hitting. For some reason this string not durable in crosses.
From: Steve, 8/11

Comments: I'm currently using NRG2 16 in the mains @ 48 on Donnay X-Blue 99. Crosses are Genesis Black Magic 16. It's the best string combo that I have used in the Donnay's. The NRG2 plays awful close to gut. It's not as powerful as gut, but more cost-effective. It plays better with a poly in the crosses than a cheap syn.
From: JT, Nashville, TN, USA. 06/11

Comments: They have tremendous feel and comfort. I have them in a hybrid, with Luxilon Alu Power Rough in the crosses. The best bang for your buck for a multifilament that is comparable to natural gut. I'm not sure about durability yet as I've only played the strings for a little over 4 hours, but so far I'm extremely impressed and will likely buy again. Tecnifibre's premiere strings.
From: Brian. 6/11

Comments: This is one of the best multifilaments out there! I am a high school player playing with a Prince 03 Speedport Black. I had this string strung at 56lbs. After a quick break-in I was able to hit with some great spin and power. I always felt like the string had good control as well. I would recommend this to any player looking for a great multifilament string that offers great spin and power.
From: Jason, Chicago, IL, USA. 4/11

Comments: These strings are really awesome I try it with a full bed with my Aeropro drive GT+ it was really good it provides the power that I need. In my other Aeropro Drive gt+ I use rpm in the mains and Tecnifibre x-one in the crosses to me I think thats the best hybrid I have ever used, I love x-one.
From: Jeff, Queens, NY, USA, 02/11

Comments: I am wanting to do a red/black colored string hybrid on my blx 6.1 tour I am thinking these strings with Babolat rpm blast, is there a better choice?
From: Aaron, Nevada, MO, USA, 01/11
(Aaron, try posting this question on our message boards in order to get suggestions and/or answers--TW Staff)

Comments: My requirements in seeking out a string were that I wanted a combination of:
1. Comfort 2. Power 3. Spin 4. Control 5. Durability
I looked at sites that had reviews on 100's of strings and based on my criterion, this was the BEST choice. Other strings don't play as well, arm stiffness etc. These string are excellent and they hold tension well.
I have a mid-size and I string one at 55 and the other at 53. And there is a noticeable difference in control when I use the 55lbs (though it still has power and spin). The 53 gives a lil more pop on the serve. Regardless....I love this string!
From: Jorge, Virginia Beach, VA, USA, 01/11

Comments: I was wrong about arm friendliness of this string. It is really good. It starts stiff but then after 2 hrs of hitting it feels much much better. So I wouldn't advise lowering string tension but get used to it. Durability is also pretty good. Really a nice alternative to natural gut and it's got tons of pop. I have switched to 17-gauge version of this string, which I think one of the best multifilaments I've ever played so far (trust me I have tried many many strings). See my review in 17-gauge. Thanks!
From: Bharath, Hillsborough, NJ, USA, 01/11

Comments: Let's get serious. This is the best bang for the buck for a hybrid set-up. It pains me to reveal this info, but string it in the mains with PSG Duraflex in the crosses at the tension of your choosing. Reap the rewards.
From: Jay, Ardmore, Pa, USA, 10/10

Comments: Used these string on cross with Luxilon ALU Rough 16L on K Blade Tour with a denser 18X20 string bed at first 57 lbs and then 54 lbs. I was very disappointed with the string, I thought it was like gut. It was the opposite. It was like hitting a brick, the ball was landing shallow and my arm was in great pain, had to cut out both strings. Be careful on what you read. I'm a very hard hitter, so these string caused my arm to hurt for a week.
From: Lefty, Vancouver, Canada, 09/10

Comments: Am I missing something here? I strung these on my Head Radicals at 61. I have played USTA for almost 10 years, and before switching to these strings I used Babolat Hurricane and/or Luxilon Big Bangers. For me these strings were horrendous. I practically had muscle all my balls for spin, very mediocre feel, and a sweet spot the size of the ball itself. For me it took 2 weeks (4 times a week) to break in. And even then, very little spin was provided, overall very disappointed with these strings
From: Matt, Flushing, NY, USA, 09/10

Comments: It's really similar to natural gut. If you like gut and want it with a lower price, this is your choice. Please use this string and save the cows. :)
From: Jack, Denver, CO, USA. 09/10

Comments: OMG, this string is just wonderful. With power, control, and durability all in one, I just love it. To tell the truth, this string was worth more than the Prince Synthetic Gut Duraflex 16. When I had this strung with my Wilson Coral Wave at 58, I could notice a significant improvement on my groundstrokes with lots of pops and also my performance overall. Plus, my arms did not tire out or felt sore at all. I would definitely recommend this string to anyone even if the strings are a tad bit expensive and did not come in many colors.
From: Jenny, San Jose, CA, USA, 08/10

Comments: I re-strung my racquet for the first time. I rate my self as 2.5-3.0. The stringer strung 2 lbs above the range for max control and less long-balls (which was my biggest problem). I did not like these strings at first, but after hitting for about an hour, I absolutely loved these strings. No more long-balls. I was able to hit my shots with a lot of pace and a lot of top spin for the first time! My hitting partner(rated 4.0) said he noticed a HUGE improvement in the placement and power of my shots. Also, no soreness in the elbow after a 2 hr session! I didn't notice any movement of the strings either. Now...let's see how long these strings can last.
From: XANKX, Los Angeles, CA, USA. 06/10

Comments: This is the best string I've ever used, it does every thing well from hitting the slice to hitting the kick serve. It hits great topspin, which is needed for a modern game. Great string to come in and sneak in a serve in volley every once in a while. The only things I didn't like about it was it isn't very durable and moves frequently. I would give it a 9.75/10
From: Kyle, Birmingham, Alabama, U.S. 01/10

Comments: I don't like this string, because it breaks very fast. However, the playability is good, but it doesn't worth to restring every 2 days.
From: Tomi, Budapest, Hungary 08/09

Comments: Well, I have been viewing the comments posted about this string. Some are saying that this string has too much power, so string it high. Here is a suggestion: If you are the type of player who has to hit 100 mph ground strokes, then maybe you should just hit with a piece of wood for direct transmission. Or maybe hit with metal wire, that will give you bite and control. My point is this: Learn how to swing the frame. It goes like this: The best string produced is Babolat VS TEAM 17. Then there is Tecnifibre X-One Biphase. Its simple to understand this string is a pleasure to hit with. Oh, and thanks for saving my arm too Tecnifibre.
From: Bear, PA, 07/09

Comments: I had strung this string fairly high (62) and I was very disappointed; I found little control and WAY too much power. It was like a trampoline.
From: James, NM 06/09

Comments: Strung X1 16g at 62 lbs mains with synthetic crosses, tension loss after about 4+ hours, main strings moved a lot after playing with a lot of spin. Previously tried X1 in 17g, tension held better than 16g, less string movement, but too much power. Probably 16g better suited for stringing as crosses.
From: James, Walnut Creek, CA. 04/09

Comments: Good strings with excellent feel and pop but not very durable
From: John, nj. 3/09

Comments: Great string. Hands down my favorite string that I have used so far. I personally have strung on both the mains and crosses. It's pretty durable, I get about half a month to a month with them. Color is nice and gives the most control and pop on serve.def worth giving a try. strung mine at 57lbs
From: chris, Marengo, Illinois, U.S. 2/09

Comments:The X-One Biphase 16's are excellent if you are a player with heavy topspin. Strung at 54 as crosses with Luxilon Big Banger as the mains, the strings lasted about three days with an average of three hours of hitting per day. The mains were broken in and lively but the Biphase's started to wear as if the too much topspin had thinned it down and the sweet spot literally looked like it was made of cloth. The only problem is the durability, other than that, no complaints.
From: Hoang, Piscataway, NJ, USA. 1/09

Comments: These strings do everything well. Good power and very lively off the strings. Yet still good control and good spin on delicate shots. Feels soft and spongy which may be reason why I feel the sweet spot has expanded. Durability is good. It frayed in time, but still plays well. For people who demands more from their strings.
From: Roy, Houston, TX, USA, 10/08

Comments: Wonderful string- for the first hour or two it felt stiff, but then it relaxed and hits beautifully with more feel and power than the old 515 or the NXT Tour. Using Maxply Macenroes with extra weight on the handle and at 3 and 9 o'clock positions, strung at 55 lbs and the response is amazing. String has begun to move a little but nowhere near the way the 515 or NXT Tour moved. Very satisfied.
From: Harry, Brampton, ON, Canada, 08/08

Comments: Watch out the red strings look and feel very different from the clear ones. I used the clear ones for over a year and love them. When I saw the pros playing with those red strings, I thought it be cool to play with similar looking strings. Well watch out for the cool factor. It is a waste. I was playing with my best tennis buddy, and he had a clear set of X-One Biphase. I had my red set. To the touch, the strings felt completely different. My friend did not even believe they were the same strings. The clear one feels like a top-notch multi-filament synthetic gut. The red one feels like cheap slippery single filament cheap nylon. I have a spare set of reds, and I am returning and exchanging them for a set of clear ones. Just saw a video of John Isner, and he did play with the red ones. I'll leave those to him. I am not trying to be cool anymore. I just want the best strings, and it is the clear ones.
From: Guy, Mill Valley, CA, USA. 03/08

Comments: I was using Babolat Pro Hurricane Tour, but it was killing my elbow. Now this stuff is incredible! Freshly strung, it's very powerful, but pockets the ball so well that control is perfect. It doesn't dampen vibration as well as I'd like, but of course a nice "US OPEN" dampener takes care of that. Highly recommended.
From: Alex, The Woodlands, TX, USA. 1/08

Comments: I use ALU Rough crosses and Babolat gut mains at 60#. More powerful than gut, and 1/4 of the durability. Going with poly crosses gives you a much stiffer, more control oriented stringbed than poly mains. I went through 4 sets of this string to just one of my gut. I play with a Flexpoint Prestige MP, so my strings last much longer than in other racquets. Because of that, price isn't an issue. I like the string just fine, but it is not a substitute for gut.
From: Roy, Santa Rosa, CA, USA, 08/07

Comments: Exceptional string. Very responsive, very good feeling, good spin and high precision. Average durability but very willing to have average durability for the other exceptional qualities.
From: Anon, Switzerland, 07/07

Comments: The string does have a nice feel to it but different. Way too much power and it just didn't produce the topspin control that NXT does. I'm going to stick to NXT. Pure Drive 60#
From: Thomas, Evansville, IN, USA, 06/07

Comments: This string in term of feel and durability are much better than Wilson NXT Tour 16 that I had before, it hold the ball longer, and better in control. I string at 59 pound on my Prince Tour Graphite Classic Original Mid.
From: Ken, Cypress, CA, USA. 6/07

Comments: Strung in a KSix-One Team at 55lbs. Way too powerful, too springy, too slick. It might be OK if you want to string at the maximum rec. tension. But I'm switching to something crisper (original sensation, which came in the racquet, is much crisper) with much better durability. At 14.50 a pack, don't expect a miracle: it's an elastic multi that will fray very quickly.
From: JD, Brownsville, Texas, USA, 06/07

Comments: For power and feel this is the best string out there - plays like gut. I've tried all the strings in the comment below, plus more. I've also tried a number of polys and hybrids. As far as control some of the polys may have the edge, but if you don't mind some power this string is the best out there.
From: Ryan, Redondo Beach, CA, USA, 06/07

Comments: This is the best string I have tried so far. I have gone through many multifilament strings, NXT, NXT Tour, Bab. Excel, K Gut, K Gut Pro and VS Gut and none of them hold tension as well or as comfortable as X-1 Biphase. This string holds up to all good comments mentioned in my opinion. KFactor Six-One 95 at 57lbs.
From: Brian, Laguna Niguel, CA, USA. 5/07

Comments: Looks like I am the only female. I tried NXT before and loved it a lot, so I loved multi's. And then I looked for a much better multi, and found biphase. I strung it at 56, pretty stupid. And I also had lead tape on my racquet. And my shots very going out, so I ripped off all the lead tape on my racquet and the power went down. And is the right power to me. This is a great string. My string started to fray so I invested in some string savers. And love this string a lot. A perfect mixture of Power, Control, Comfort, spin. Love this, and for sure use it again. Next time I will string it at 63.
From: Kathleen, NY, USA, 03/07

Comments: Yep, this is the string. Outstanding power and control. Feel is not quite as good as some of the Babolat strings, but all things considered (incl. durability), this is the best I've used. I've had it in my Babolat Aeropro for the last year. I agree with an earlier comment: string toward the high range for best control.
From: Brian, Mill Valley, CA, 03/07

Comments: This string is great. I really like it. Warning: Very powerful...so string it high.
From: Anon, 02/07

Comments: Unbelievable, you cannot get a better string than this. I used gut before, but I love this string more than the gut and it's half the price of gut and it's as good as gut. I love this string more than NXT, and NRG2. I got excellent amount of power, perfect control, 100% comfort. I have tennis elbow, and after a session I felt no pain in my elbow. My backhands were much better; my serve is way better. I say this is the best string I tried in 10 years. And I am shocked I didn't come across this earlier. If you like NXT, and NRG2 and thought that they were awesome wait till you try this string, it will just blow you away. I was 200% happy about this string. In this review people were unhappy about was the durability, I solved that by investing in string savers, so the durability increased.
From: Andy, NJ, USA, 01/07

Comments: I have to say that this string blows all strings out of water. I have never hit with a string with more power, control, and feel. I mean the power and ball striking you get is incredible. On serves, the ball just explodes on kicks and flat serves. The strings don't move, so its kind of like big banger in that there is controlled spin. I have nrg2, which is outstanding, but this is a step above. This is worth the extra 2 bucks over nrg2.
From: Colin, Alaska 09/06

Comments: I strung Luxilon Big Banger Alu Power 16 on my Pure Drive Standard because I heard it was a good string. It was durable, but it was killing my arm. So, I decided to cut it off and put new string on. X One 16 is a really nice string. It gave me drastic improvement on my strokes and especially my serve because this string has a lot of power. Don't get me wrong; it doesn't make your racquet a springboard. I've played with this string for about a month, about 4 or 5 days a week, and the string is still good and still has power. The string started to move during the beginning of the 3rd week though. X One has excellent feel, power, and comfort, but it isn't good with slices and drop shots. While it is still possible to do a decent drop shot or slice, its thickness, most likely, makes it harder to do good slice and drop shots. Nonetheless, this is a very, very good string.
From: Jacque, Seattle, WA, USA 07/06

Comments: I usually string with gut because I have both wrist and shoulder problems. I decided to try Biphase because of all the great reviews and its arm-friendly nature. The previous post was right on - it takes about two to three hours to settle in and then plays fantastic. Not as much power as gut but just as much control, touch and comfort. I'm sold - this is my new string of choice. I use a Head Flexpoint Instinct strung at 60 lbs. and also get less vibration than gut with this string. You owe it to yourself to give this excellent string a try!
From: Joel, Studio City, CA USA

Comments: This string is fantastic!! I am a high school tennis player and I have tried many different strings in my tennis playing career. I have went from Wilson NXT, NXT Tour, Sensation, Reaction, Gamma Live Wire, TNT, TNT2, and many others. I have found that Tecnifibre X-One Biphase gives me the most spin potential and most pop off my forehand. The string takes a couple hours to get broken in, but after that it is sensational!!! I recommend this string to anyone that is looking for great spin and exceptional power. Strung on a Babolat Z-Tour at 60-62 lbs.
From: Mark, Cookeville, TN USA 03/06

Comments: I played with it for a little over a month. Durability was not as good as I wanted so I switched back to another string when it broke. My advice is if you don't want to get hooked don't try it. I hate the price but now I have to have it. I definitely noticed a drop off when I switched back to my old string. The feel is better than anything I have tied. You get rewarded when you hit thought the ball with solid strokes. You can feel the ball pocket and other than throwing the ball over I don't know how I can get more control out of a string...I mean a sting that has some pop. I started to place the ball deep in the corner with regularity. I beat a guy 6-7, 6-2 and 6-1 that I had never even taken a set off of before. The string did not make me instantly better but it gave me the confidence to go for more shots. The more I hit with it the more confidence I gained and the better I got. I hate that I like it because it is not cheap. But now I can't afford not to play with it. I play with a Prince Diablo Tour strung at 63 Lbs
From: Rondall, Clinton, MD, USA

Comments:I used to use Luxilon Big Banger and it was just killing my arm. I tried an arm friendly string Wilson Sensation and hated it. Then I tried the X-one Biphase and it was great. No arm pains and hitting with great pace. I had good topspin coming of the racquet. I felt I had good control and the string has decent durability. I would not say great durability. It is a powerful string. I would recommend the string. I am going to try the Tecnifibre NRG2 and compare. Strung on a Babolat Pure Power at 56lbs.
From: Dave USA 07/05

Comments: Amazing string. I would not have tried it because of the price tag but ordered a used racquet off the boards and it came strung with this. Amazing power and comfort. Great control and feel. I definitely recommend it. Once I become manager of my McDonalds I will definitely be ordering my own packs.
From: Mike, Milwaukee, WI Usa 07/05

Comments: I didn't want to like it, because of the price tag, but I was given some test string.... WOW, very comfortable and pretty powerful stuff! My opponents said it was the best I have ever played. It wasn't like my game only improved a little, It was dramatically better. Lots of pop, very similar to gut, pocketed well and my control was decent. No fraying in 3 hours. Gotta say, it is probably worth the money. I am used to buying 4 buck poly or synthetic... ooh this is gonna hurt, but it might be the secret ingredient to my plan for COMPLETE WORLD DOMINATION!
From: Hedley Biphase, Southside, VA, USA

Comments: What a great arm friendly string. I really didn't like it at first because I was into experimenting with expensive polyesters and wasn't used to the feel. After a few matches I felt the tension hold was really good and the durability a surprise because it lasted as long as some polyester's I have used. Most definitely worth the bling.
From: Eugene, NY, NY, USA. 02/05

Comments: The softest and fastest string I ever tried. I use it for cross strings with monofilament mains.
From: David, former pro, USA. 02/05

Comments: Great string, exceptional feel and great power with just enough control. I love this stuff! (I'm an all-court 5.5 player who strung his Head i.Prestige MP XL at 62lbs.)
From: Damion, Los Angeles, CA, USA. 07/04

Comments: My favorite string from Tecnifibre. Although it is less lively than NRG2, it has good power (especially compared to NXT). It is very controllable, largely due to its notable ability to impart spin. Tension maintenance in this string is also better than Tecnifibre's previous offerings. I have gotten relatively good durability from this multifilament (aside from providing superb comfort, the polyurethane also seems to lessen string movement). However, string breakers on a budget might be weary of the price. Strung in a
From: Dunlop 200G XL @ 71lbs).
Dean, Appleton, WI, USA. 5/04

Comments: Plays similar to Tecnifibre NRG2, but is crisper and slightly less powerful. String bed doesn't get as mushy as Tecnifibre NRG2 or Wilson NXT. The durability and tension maintenance is much better. Plays similar to Laser Fibre Phenom and Klip Excellerator.
From: Michael, Raleigh, NC, USA. 4/04

Comments: The softest and closest feel to natural gut. The durability is okay. Try it yourself.
From: Anon. 2/04