The Tecnifibre Ruff Code 1.25 tennis string brings together two innovative technologies: Thermocore & Biphase. The Thermocore, in which varied heating & cooling temperatures are used, softens the string to reduce vibrations. The Biphase allows for 10% better tension maintenance. This co-poly string has textured surface for better spin, which, combined with its thinner gauge, makes it comfort & control-oriented to let you perform better. The string is supplied in a 200m (660ft.) reel & has a gauge of 1.25mm (17L).