String comparison
X-One Biphase vs Rexis Comfort
Tecnifibre X-One Biphase against Yonex Rexis Comfort: ratings, specs and which one fits your junior.
The short answer
Both are multifilament strings. X-One Biphase leads on power, durability and tension hold. They score the same for arm friendliness (5/5).
Ratings
Power
Spin
Control
Comfort
Durability
Tension hold
Ratings are on a 1–10 scale. The higher score is in bold when they differ.
Pick X-One Biphase if…
- You want more power (9 vs 8 out of 10)
- You want more durability (5 vs 4 out of 10)
- You want more tension hold (7 vs 6 out of 10)
- You restring often and want it cheaper to keep up (cost score 3/5 vs 2/5)
- Best for: players wanting natural gut feel without gut price
- Best for: those with arm issues or tennis elbow
- Best for: flat hitters with slow to medium swing speeds
Pick Rexis Comfort if…
- Best for: players with tennis elbow or arm issues
- Best for: veterans with shorter swings
- Best for: beginners wanting premium comfort
Specs side by side
| Spec | X-One Biphase | Rexis Comfort |
|---|---|---|
| Type | Multifilament | Multifilament |
| Construction | High Heat Capacity (H2C) fibers with Biphasic trimerization process and polyurethane immersion | Multifilament with FORTIMO (highly elastic polyurethane by Mitsui Chemicals) plasma-bonded to nylon filaments |
| Gauges | 16, 17, 18 | 16, 16L |
| Stiffness | Low | Low |
| Set price | $18–22 | $18–22 |
| Reel price | $200–250 | $190–230 |
| Arm friendliness | 5/5 · Excellent | 5/5 · Excellent |
| Cost to maintain | 3/5 | 2/5 |
| Recommended from | Age 8 | Age 8 |
| Levels | Beginner, Intermediate, Advanced | Beginner, Intermediate |
| Play styles | All court, Serve and volley, Touch player | All court, Touch player, Beginner |
| Junior tension | 52-56 lbs for juniors. Holds tension well for a multifilament. | 52-56 lbs for juniors. |
X-One Biphase in short
X-One Biphase is Tecnifibre's premium multifilament that combines their best technologies into a single string. The patented Biphasic process with visible marks extends string life by 20% while the H2C fibers allow extreme temperature treatment during manufacturing. Multifilament fibers are immersed in polyurethane for shock absorption and optimum comfort. Many users say "I've never tried natural gut, but X-One Biphase is what I imagine it would feel like." Easily one of the more powerful multifilaments available with cloud-like comfort even at higher tensions.
Rexis Comfort in short
Yonex Rexis Comfort is Yonex's softest high-end multifilament, built with FORTIMO - a highly elastic polyurethane developed by Mitsui Chemicals. The resin is plasma-bonded to nylon filaments at the molecular level for improved repulsion and durability. "Best String for Tennis Elbow" - many report it's the only string that let them continue playing after months of pain. Plush, smooth and connected feel that pockets the ball beautifully. Touch shots, lobs and drop shots are especially easy. Limited durability (some report 2.5 hours) - better suited for up to 4.0 level players.
X-One Biphase vs Rexis Comfort: quick answers
Which has more spin, X-One Biphase or Rexis Comfort?
They tie on our spin rating (5/10 each).
Which is more arm-friendly for a junior?
They score the same, 5/5. X-One Biphase is recommended from age 8 and Rexis Comfort from age 8.
Which lasts longer?
Tecnifibre X-One Biphase rates 5/10 for durability against 4/10.
Which is cheaper?
X-One Biphase costs about $18–22 a set and Rexis Comfort about $18–22, at typical retail.
The short answer and the "pick if" lists are generated from our ratings and junior data only. Data verified 2025-01 (X-One Biphase) and 2025-01 (Rexis Comfort).