The Tecnifibre Duramix HD 1.30 tennis string has been developed to provide comfort & outstanding durability, which is the effect of multifilament construction reinforced with polyester & manufactured with the use of a new formula for the high density polyurethane that replaces standard PU. The users will definitely enjoy the feel from this string that is crisp & precise. It has a gauge of 16L (1.30 mm) & the length of the set is 12.2m (40ft).