Luxilon ALU Power: the benchmark copoly string
Luxilon ALU Power is used by more professional tennis players than any other string in the world, and it earns that position through genuinely exceptional control and spin. The slightly rounded edge profile (square-cut profiles typically bite more on spin generation but are harsher on arms) provides a good balance of spin and arm comfort relative to other pro-level colopies. The string holds tension reasonably well compared to other co-poly options, though restringing every 20 to 30 hours is still recommended for consistent feel.
Check price on Amazon →We compared the leading co-polyester tennis strings to find which offer the best combination of control, spin, arm comfort, and durability for competitive players.
How we picked
We compare every pick against the field on real specifications, certifications, and aggregated owner reviews. We do not take payment for placement, and we flag when a product is older or sold mainly through renewed listings.
Top picks compared
| Pick | Best for | Score | |
|---|---|---|---|
| Luxilon ALU Power: the benchmark copoly string | Check price | ||
| Babolat RPM Blast: best for maximum spin generation | Check price |
Our picks up close
Luxilon ALU Power: the benchmark copoly string
Luxilon ALU Power is used by more professional tennis players than any other string in the world, and it earns that position through genuinely exceptional control and spin. The slightly rounded edge profile (square-cut profiles typically bite more on spin generation but are harsher on arms) provides a good balance of spin and arm comfort relative to other pro-level colopies. The string holds tension reasonably well compared to other co-poly options, though restringing every 20 to 30 hours is still recommended for consistent feel.
Babolat RPM Blast: best for maximum spin generation
The Babolat RPM Blast, used most famously by Rafael Nadal, is shaped with an octagonal cross-section that creates significantly more string-to-ball bite than round-profile strings, producing higher spin rates. For heavy topspin players who want to push the limits of spin generation, RPM Blast edges out ALU Power in bite and revolutions.
Before you buy
Gauge
Thinner gauges (1.20 to 1.25mm) provide more spin, feel, and control at slightly reduced durability. Thicker gauges (1.30 to 1.35mm) are more durable for string-breakers but feel stiffer. Most players start at 16L (1.25mm) and adjust based on durability needs.
Shape
Round profiles are the most comfortable. Shaped profiles (pentagonal, octagonal, hexagonal) bite the ball more for spin at the cost of harshness. Try shaped strings only after confirming your arm tolerance for stiffer strings.
Softness additives
Some copoly strings incorporate plasticizers or softer additives that reduce stiffness significantly. Strings marketed as "soft copoly" or "comfort poly" are worth considering for players concerned about arm health who still want copoly performance.
String pattern compatibility
Open string patterns (16x19) maximize spin from copoly strings. Dense patterns (18x20) reduce the effect. If you are switching to copoly specifically for spin, playing in a racket with an open pattern amplifies the benefit.
Hybrid stringing
Stringing copoly in the mains with a softer multifilament in the crosses reduces arm stress while retaining most of the control benefit from the poly mains. This is the most common setup used by professional players who are concerned about arm comfort.
Restringing budget
Copoly strings that are not changed regularly become dead and cause more arm stress than fresh strings. Budget for restringing every 20 to 40 hours of play. A stringing subscription from your local shop can make this affordable and automatic.
Quick answers
A copoly (co-polyester) string is made from a polyester blend that combines the control and spin benefits of pure polyester with improvements in feel and arm comfort. Most co-poly strings incorporate additives or modified extrusion processes that give them a slightly different playing character than pure polyester.
Copoly strings are not ideal for beginners. They are stiff, require a full swing to generate power, and are harder on the arm than multifilament or synthetic gut strings. Beginners should start with synthetic gut or multifilament strings and progress to copoly once they have developed consistent groundstrokes.
Co-polyester strings lose tension significantly in the first 24 hours after stringing and continue to drop throughout use. Most players should restring every 20 to 40 hours of play, or as a guideline, as many times per year as you play per week. Playing on dead poly causes arm stress and loss of control benefits.
String 10 to 15 percent lower tension than you would use with nylon strings. Copoly's inherent stiffness at the same tension as nylon will produce a very board feel. Lower tension compensates for the stiffness and provides the comfortable, pocketing feel that quality copoly is known for.
