String Project Keen, thin-gauge monofilament tennis string
String Project Keen is a thin-gauge monofilament tennis string, a concentrate of technology that is incredibly solid and responsive. Available in 1.13 mm, 1.18 mm and 1.22 mm gauges, it is designed for those seeking a high-performance string without sacrificing sensitivity. Arm Friendly® certified with 8.5/10 comfort.
- Arm Friendly® Monofilament
- Gauges 1.13 · 1.18 · 1.22 mm
- High-sensitivity thin gauge
- Tension 18–23 kg
Playing profile
String Project Keen offers excellent spin (9/10), amplified by the thin gauge that grips the ball more effectively. Comfort (8.5/10) is surprising for such a thin string, thanks to Arm Friendly® certification. Power (8/10) is responsive and immediate, while resilience (8.5/10) ensures durability beyond expectations.
- Spin9/10
- Comfort8.5/10
- Resilience8.5/10
- Power8/10
- Control7.5/10
- Tension7/10
Ratings and technical specifications measured in the laboratory by Pro-t-one (Eng. G. Medri) — laboratory test report 1.18 mm (PDF).
Extreme performance and sensitivity on court
On court, Keen offers a unique playing experience thanks to its thin gauge. The feel is direct, sensitive and communicative: every nuance of impact with the ball is clearly perceived. Spin is naturally amplified by the reduced diameter, which grips the ball more effectively. Responsiveness is immediate, with an explosive drive that is surprising for such a thin gauge.
Direct feel and extreme sensitivity
Keen's thin gauge offers a direct, sensitive feel that standard gauges cannot match. Every nuance of impact is clearly perceived, enabling precise adjustments.
- Direct, communicative feel
- Superior touch sensitivity
- Gauges from 1.13 to 1.22 mm
- Precise impact perception
Amplified spin and immediate responsiveness
With 9/10 spin and 8/10 power, Keen uses its thin gauge to grip the ball more effectively. Responsiveness is immediate and drive is explosive, with surprising resilience (8.5/10).
- Spin 9/10 amplified by the thin gauge
- Power 8/10, responsive and immediate
- Surprising 8.5/10 resilience
- Fast, effective snap-back
Design optimised for the thin gauge
String Project Keen is a concentrate of technology designed to make the most of the advantages of a thin gauge. Its optimised monofilament construction ensures surprising solidity and responsiveness despite the reduced thickness. The thin gauge naturally increases grip on the ball, amplifying spin and offering a direct, sensitive feel that standard gauges cannot match.
The manufacturing processes
Spring Load
This technology allows the molecular chains to contract repeatedly, resulting in minimal tension loss and, above all, greater stability of the string's properties.
Double Heating
The "heat treatments" remove internal stresses and even out any irregularities in the string. They also make the strings more flexible and elastic.
Liquid Wax
The string is finished with a layer of wax. This treatment significantly extends its lifespan by reducing wear and making stringing easier.
Low Friction
Reducing the string's friction delivers reduced string movement, greater spin potential thanks to improved snap-back, and a longer lifespan.
Technical data sheet
| Feature | Value |
|---|---|
| Type | Arm Friendly® thin-gauge monofilament |
| Cross-section | Round |
| Gauges | 1.13 mm (18) · 1.18 mm (17) · 1.22 mm (16L) |
| Dynamic stiffness | 228 g/mm |
| Manufacturing processes | Spring Load, Double Heating, Liquid Wax, Low Friction |
| Recommended tension | 18–23 kg (with thin gauges it is best not to exceed 22 kg) |
The right string if you see yourself here
Those seeking extreme sensitivity
Players who want to perceive every nuance of impact with the ball and prefer a direct, communicative feel that only a thin gauge can offer.
Spin-oriented players
Those who want to maximise rotation by exploiting the natural advantage of a thin gauge, which grips the ball more effectively than standard gauges.
Those seeking comfort in a thin gauge
Those who normally avoid thin gauges for fear of stiffness: Keen is Arm Friendly® certified with 8.5/10 comfort, ensuring arm protection even with the reduced thickness.