6-SIDED SPIN GENERATING POLY: Solinco "Heaven Strings" Revolution Blue Colored 6-Sided Poly (Polyester) Tennis Racquet String Sets are designed for intermediate and advanced players alike who value spin, control, and ball pocketing on heavy topspin and slice shots. The hexagonal shape bites into the ball, resulting in far greater revolutions per second than a cylindrically shaped string ever could. The snapback is crisp, and the ball feel on these strings is excellent. STRING COMPOSITION: Co-polyester Monofilament PERFECT HYBRID SETUP: Advanced players and pros alike have been using a hybrid string setup, where (2) half-sets of different types of strings are combined to form a bed with many desired characteristics. An excellent example of this is how a poly, spin-inducing string such as Solinco Revolution can be paired with a softer multifilament. The result is a softer and more lively string bed - with the added durability and spin generation of the poly string - the best of both worlds! Solinco "Heaven Strings" Revolution Blue Colored 6-Sided Poly (Polyester) Tennis Racquet String Sets are the best choice for the pro or advanced player looking for massive spin potential in a medium-stiff poly that will last more than a few sets. They are often used as one half of a hybrid setup, generally with a softer string like a multifilament in order to increase playability without sacrificing too much durability.Length: 40 feet / 12.2 metersComposition: Co-polyester MonofilamentControl: 8 out of 10Durability: 8 out of 10Spin: 8 out of 10Playability: 7 out of 10Power: 7 out of 10Comfort: 7 out of 10