Ashaway PowerNick 18 squash string features a monofilament Zyex core encapsulated with a high tenacity monofilament nylon wear surface for players looking for superior durability and playability. For players who are looking for superior durability and playability. Tremendous power from dynamic stiffness of Zyex monofilaments. Excellent tension stability at all tensions. Optimum combination of power and durability.