String comparison
AK Pro CX vs Power Fiber Pro
Gosen AK Pro CX against Volkl Power Fiber Pro: ratings, specs and which one fits your junior.
The short answer
Both are multifilament strings. AK Pro CX leads on spin, control, durability and tension hold. For a junior with arm concerns, Power Fiber Pro is the safer choice.
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 7 out of 10)
- You want more durability (6 vs 5 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 4/5 vs 3/5)
- Best for: players wanting control with comfort
- Best for: those with arm sensitivity
- Best for: all-court players with longer strokes
Pick Power Fiber Pro if…
- Arm comfort comes first (arm friendliness 5/5 vs 4/5)
- Best for: juniors with arm sensitivity who want control
- Best for: players moving up from a plush multifilament
- Best for: all-court players with full strokes
Specs side by side
| Spec | AK Pro CX | Power Fiber Pro |
|---|---|---|
| Type | Multifilament | Multifilament |
| Construction | Umishima structured monofilament surrounded by heat resistant polyamide fibers with CX composite micro fiber | Multilayer polyamide multifilament: thin-fiber core, polymer layer, two layers of thicker fibers and a polymer jacket; firmer polymer than Power Fiber II |
| Gauges | 16, 17 | 15L, 16, 17, 18 |
| Stiffness | Medium | Low |
| Set price | $12–16 | $13–15 |
| Reel price | $120–150 | — |
| Arm friendliness | 4/5 · Good | 5/5 · Excellent |
| Cost to maintain | 4/5 | 3/5 |
| Recommended from | Age 10 | Age 10 |
| Levels | Intermediate, Advanced, Elite | Beginner, Intermediate, Advanced |
| Play styles | All court, Baseliner, Touch player | All court, Touch player, Serve and volley |
| Junior tension | 52-58 lbs for juniors. Very arm-friendly with good control. | 50-56 lbs for juniors. |
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.
Power Fiber Pro in short
Volkl Power Fiber Pro is a firmer, more controlled and more durable version of Power Fiber II. Bigger filaments of a firmer polymer give it more control than a typical soft multifilament, while it still absorbs shock and vibration. Reviewers rate its power and feel above average and its spin below average, and durability reports are mixed. It comes in four gauges and several bright colors.
AK Pro CX vs Power Fiber Pro: quick answers
Which has more spin, AK Pro CX or Power Fiber Pro?
Gosen AK Pro CX, with a spin rating of 7/10 against 5/10.
Which is more arm-friendly for a junior?
Volkl Power Fiber Pro scores 5/5 for arm friendliness, against 4/5 for AK Pro CX. It is recommended from age 10.
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 Power Fiber Pro about $13–15, 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 2026-10 (Power Fiber Pro).