Duramix HD offers the best combination of durability and comfort. Designed with PU HD for limited elasticity for firm feel and great control and features a polyester and polyamide multifilament blend for surprising soft and crisp feeling. Also with SPL, an anti abrasion coasting increased durability. Color(s):Natural Composition:50% Polyester, 50% Polyamide Multifilaments Gauge:17g (1.25mm) Length:660' Type:Polyester Multifilament Tecnifibre Tennis String btdhd6-17