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 Sirius
For an unbeatable experience and top-level performance.
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 top-of-the-range control (9.5/10), spin (9.5/10) and power (9/10), Sirius is the perfect balance between performance and versatility. Arm Friendly® certified with 8/10 comfort.
8/10
Comfort
9.5/10
Spin
9/10
Power
Technical Specifications and On-Court Ratings
The Perfect Balance of Power, Control and Spin
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.
Power9/10
Comfort8/10
Control9.5/10
Resilience8/10
Spin9.5/10
Tension9/10
Ratings measured in the laboratory by Pro-t-one (Eng. G. Medri), as are the technical specifications.
Characteristics and Laboratory Tests
Developed with next-generation materials, Sirius reaches a unique performance profile in the String Project range. The combination of top-level control and spin, together with exceptional power and a dynamic stiffness of 225 g/mm, makes it a string that makes no compromises.
Technical Data Sheet
- Cross-section
- Round
- Available gauges
- 1,25 mm (16) · 1,30 mm (16)
- Dynamic stiffness
- 225 g/mm
- Tension range
- 17 / 23 Kg
Laboratory test report · Pro-t-one (Eng. G. Medri)
Optimised Technology and 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 (9.5/10) and spin (9.5/10), together with exceptional power (9/10), makes it a string that makes no compromises. The 225 g/mm dynamic stiffness ensures an optimal balance between responsiveness and comfort.
The manufacturing processes
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.
An Exceptional Playing Experience
On court, Sirius stands out for its completeness: every aspect of the game is enhanced without compromise. Surgical control (9.5/10) lets you place the ball with millimetric precision, spin (9.5/10) generates complex, effective rotation, and power (9/10) 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
What the Experts Say
Independent reviews published by testers and specialist outlets.
Who It's For
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.
Ready to Reach the Top Level?
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 Sirius
What is String Project Sirius?
String Project Sirius is a monofilament tennis string developed with next-generation materials. It offers control (9.5/10), spin (9.5/10), power (9/10) and Arm Friendly® comfort (8/10), with tension maintenance (9/10). It is the most complete and balanced product in the String Project range.
At what tension should String Project Sirius be strung?
The recommended tension range is between 17 and 23 kg. The wider range compared to the other strings in the range lets you customise the setup to your playing style: lower tensions for power and comfort, higher for maximum control.
Which gauges is String Project Sirius available in?
Sirius is available in two gauges: 1.25 mm (16L) for maximum spin and sensitivity, and 1.30 mm (16) for greater control and durability.
Is String Project Sirius suitable for players with arm problems?
Yes, Sirius is Arm Friendly® certified with 8/10 comfort. Despite its high power and spin performance, its construction with next-generation materials ensures good vibration absorption.
What is the difference between String Project Sirius and String Project Magic?
Sirius offers higher performance in control (9.5 vs 7.5/10), spin (9.5 vs 9/10) and power (9 vs 8/10), while Magic excels in comfort (9 vs 8/10). Sirius is more oriented towards complete performance, Magic towards comfort with monofilament performance.
How long does String Project Sirius last?
Sirius has 9/10 tension maintenance, among the best in the range. It keeps its playing characteristics consistent for longer than most polyesters, guaranteeing reliability session after session.