String Project Sirius, monofilament tennis string
String Project Sirius is a monofilament tennis string developed with next-generation materials, designed to deliver high-level performance and an exceptional playing experience. With control, spin and power at the top of the range, Sirius is the perfect balance between performance and versatility. Arm Friendly® certified with 8/10 comfort.
- Arm Friendly® Monofilament
- Gauges 1.25 · 1.30 mm
- Next-generation materials
- Tension 17–23 kg
Playing profile
String Project Sirius offers a complete, balanced performance profile: absolute top-of-the-range control (9.5/10) and spin (9.5/10), combined with power (9/10) that lets you drive the ball with ease. Tension maintenance (9/10) ensures consistent performance over time, while Arm Friendly® comfort (8/10) protects the arm.
- Control9.5/10
- Spin9.5/10
- Power9/10
- Tension9/10
- Comfort8/10
- Resilience8/10
Ratings and technical specifications measured in the laboratory by Pro-t-one (Eng. G. Medri) — laboratory test report 1.25 mm (PDF).
An exceptional playing experience
On court, Sirius stands out for its completeness: every aspect of the game is enhanced without compromise. Surgical control lets you place the ball with millimetric precision, spin generates complex, effective rotation, and power offers natural, consistent drive. The feel is direct and communicative, with Arm Friendly® comfort that protects the arm.
Top-level control and spin
Sirius offers absolute top-of-the-range control (9.5/10) and spin (9.5/10). The combination of next-generation materials and advanced manufacturing processes lets you direct every shot with precision and generate effective rotation.
- Surgical 9.5/10 control
- Exceptional 9.5/10 spin
- Precise directionality
- Complex, controlled rotation
Natural power and Arm Friendly® comfort
With 9/10 power and 8/10 Arm Friendly® comfort, Sirius offers natural, consistent drive without tiring the arm. Tension maintenance (9/10) ensures these performances remain consistent over time.
- Natural, consistent 9/10 power
- Arm Friendly® comfort 8/10
- 9/10 tension maintenance
- Consistent performance over time
Optimised performance
String Project Sirius 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 power, makes it a string that makes no compromises. The dynamic stiffness of 225 g/mm ensures an optimal balance between responsiveness and comfort.
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.
Pre-Stretch
Thanks to the "pre-stretch" of the core, the entire string minimises tension loss while at the same time allowing a lower stringing tension.
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® Monofilament (next-generation materials) |
| Cross-section | Round |
| Gauges | 1.25 mm (16L) · 1.30 mm (16) |
| Dynamic stiffness | 225 g/mm |
| Manufacturing processes | Spring Load, Pre-Stretch, Double Heating, Liquid Wax, Low Friction |
| Recommended tension | 17–23 kg |
The right string if you see yourself here
Competitors seeking the very best
Those who want a string that excels in every aspect: control, spin, power and tension maintenance. Sirius is the choice for those who accept no compromises.
Demanding amateurs
Those seeking high-level performance with the versatility to adapt to different playing styles. Sirius offers the best in every situation.
Those who want consistent performance
Those who need the string to keep its characteristics over time: with 9/10 tension maintenance, Sirius guarantees reliability session after session.