EFFECTING - Its octagonal high-density copolyester structure provides phenomenal ball rotation and exceptional effect taking. CONTROL - Like all of our RPM cords, the HURRICANE RPM string gives you a lot of control for precision in every strike. Its special low density copolyester gives you even more flexibility. Perfect for players who want greater tolerance. RESISTANCE - The copolyester compound of the RPM range gives particularly strong monofilaments. Perfect for players who hit hard and want performance that lasts.