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.
Arm Friendly®
String Project Keen
A concentrate of technology, incredibly solid and responsive.
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.
8.5/10
Comfort
9/10
Spin
8/10
Power
Technical Specifications and On-Court Ratings
Thin-Gauge Sensitivity and Responsiveness
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.
Power8/10
Comfort8.5/10
Control7.5/10
Resilience8.5/10
Spin9/10
Tension7/10
Ratings measured in the laboratory by Pro-t-one (Eng. G. Medri), as are the technical specifications.
Absolute Comfort and Feel
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.
Technical Data Sheet
- Cross-section
- Round
- Available gauges
- 1,13 (18) · 1,18 (17) · 1,22 (16L)
- Dynamic stiffness
- 228 g/mm
- Tension range
- 18 / 23 Kg
Laboratory test report · Pro-t-one (Eng. G. Medri)
Technology and Design Optimised for the Thin Gauge
String Project Keen is developed with next-generation materials that give it a unique performance profile in the range. The combination of top-level control and spin, together with exceptional responsiveness, makes it a string that makes no compromises. The 228 g/mm dynamic stiffness ensures an optimal balance between responsiveness and comfort.
The manufacturing processes
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.
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
What the Experts Say
Independent reviews published by testers and specialist outlets.
Who It's For
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.
Ready to Discover Extreme Sensitivity?
Choose the format that best suits your needs. Free shipping from €50.
200 m Reel
~17 stringings
-
~€6.41 per stringing
- Free shipping
- 1 Dampener
- 2x Dry Overgrip pack
Gauge:
Pack of 6 Sets
6 stringings
-
~€8.98 per stringing
- Free shipping
- 1 Dampener
- 2x Dry Overgrip pack
Gauge:
Pack of 3 Sets
3 stringings
-
~€9.97 per stringing
- Free shipping
- 1 Dampener
- 2x Dry Overgrip pack
Gauge:
Single Set
1 stringing
-
- Free shipping
- 1 Dampener
- 2x Dry Overgrip pack
Gauge:
Frequently Asked Questions (FAQ) about String Project Keen
What is String Project Keen?
String Project Keen is a thin-gauge monofilament tennis string (1.13-1.22 mm), a concentrate of technology that is incredibly solid and responsive. It offers spin (9/10), power (8/10) and Arm Friendly® comfort (8.5/10) with resilience (8.5/10) that is surprising for such a thin gauge.
Why choose a thin gauge?
A thin gauge (1.13-1.22 mm) offers significant advantages: more spin thanks to amplified grip on the ball, a more direct and sensitive feel, and immediate responsiveness. Keen is designed to exploit these advantages while keeping comfort and durability beyond expectations.
At what tension should String Project Keen be strung?
The recommended tension range is between 18 and 23 kg. With thin gauges it is advisable not to exceed 22 kg to maintain Arm Friendly® comfort and optimal durability.
Which gauges is String Project Keen available in?
Keen is available in three gauges: 1.13 mm (18G) for maximum sensitivity and spin, 1.18 mm (17G) for the ideal balance, and 1.22 mm (16L) for greater durability and control.
Is String Project Keen suitable for players with arm problems?
Yes, Keen is Arm Friendly® certified with 8.5/10 comfort, one of the highest in the range. Despite its thin gauge, its optimised construction and heat treatments ensure excellent vibration absorption.
How long does String Project Keen last compared to standard-gauge strings?
Keen has 8.5/10 resilience, surprising for a thin gauge. Tension maintenance is 7/10. Thanks to the Liquid Wax and Low Friction treatments, durability is beyond expectations for strings of this thickness, though naturally lower than thicker gauges.