String comparison
AK Pro CX vs X-One Biphase
Gosen AK Pro CX against Tecnifibre X-One Biphase: ratings, specs and which one fits your junior.
The short answer
Both are multifilament strings. AK Pro CX leads on spin, control and durability. X-One Biphase leads on power and comfort. For a junior with arm concerns, X-One Biphase is the safer choice. AK Pro CX costs less per set.
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 AK Pro CX if…
- You want more spin (7 vs 5 out of 10)
- You want more control (8 vs 6 out of 10)
- You want more durability (6 vs 5 out of 10)
- You want to spend less (from $12 vs $18 a set)
- Best for: players wanting control with comfort
- Best for: those with arm sensitivity
- Best for: all-court players with longer strokes
Pick X-One Biphase if…
- You want more power (9 vs 7 out of 10)
- You want more comfort (10 vs 8 out of 10)
- Arm comfort comes first (arm friendliness 5/5 vs 4/5)
- Your player is younger (recommended from age 8 vs 10)
- 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
Specs side by side
| Spec | AK Pro CX | X-One Biphase |
|---|---|---|
| Type | Multifilament | Multifilament |
| Construction | Umishima structured monofilament surrounded by heat resistant polyamide fibers with CX composite micro fiber | High Heat Capacity (H2C) fibers with Biphasic trimerization process and polyurethane immersion |
| Gauges | 16, 17 | 16, 17, 18 |
| Stiffness | Medium | Low |
| Set price | $12–16 | $18–22 |
| Reel price | $120–150 | $200–250 |
| Arm friendliness | 4/5 · Good | 5/5 · Excellent |
| Cost to maintain | 4/5 | 3/5 |
| Recommended from | Age 10 | Age 8 |
| Levels | Intermediate, Advanced, Elite | Beginner, Intermediate, Advanced |
| Play styles | All court, Baseliner, Touch player | All court, Serve and volley, Touch player |
| Junior tension | 52-58 lbs for juniors. Very arm-friendly with good control. | 52-56 lbs for juniors. Holds tension well for a multifilament. |
AK Pro CX in short
Gosen AK Pro CX uses the unique Umishima (marine island) structure developed to enhance sharpness and high resilience. The CX fiber complements the nylon in durability and tension maintenance, creating the almost perfect tennis string with crisp and soft pocketing feel combined with polyester-like control. TW playtesters found it easy to keep the ball in play on full swings while maintaining comfort - impressive for a string with this much control.
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.
AK Pro CX vs X-One Biphase: quick answers
Which has more spin, AK Pro CX or X-One Biphase?
Gosen AK Pro CX, with a spin rating of 7/10 against 5/10.
Which is more arm-friendly for a junior?
Tecnifibre X-One Biphase scores 5/5 for arm friendliness, against 4/5 for AK Pro CX. It is recommended from age 8.
Which lasts longer?
Gosen AK Pro CX rates 6/10 for durability against 5/10.
Which is cheaper?
AK Pro CX costs about $12–16 a set and X-One Biphase 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 (AK Pro CX) and 2025-01 (X-One Biphase).