Ashaway Supernick ZX 17 Squash Squash players looking for superior durability will love the new SuperNick®ZX squash string. The multifilament nylon core allows players to hit with exacting touch and ball control. The ZX wear layer provides the ultimate durability needed to keep hitting with their desired string tension. A textured element on the string surface helps players create more spin on the ball. SuperNick®ZX combines power, touch, and spin in a multifilament. ZX encapsulation made from Zyex® filaments enhances string durability and helps with maintaining string tension.