Its finally here, Solinco Confidential Tennis String is a newly developed, versatile co-polyester string. Confidential offers improved playability, control, and vastly improved tension maintenance over the current polyester market. The strings unique four-sided shape provides optimal snap back and a surprising amount of power for a co-polyester string. Construction: Co-Polyester mono-filament (4 sided)Color: SilverGauge: 16 G / 1.30 mm | 16 L / 1.25 mm | 17 G / 1.20 mm | 18 G / 1.15 mmLength: 660 ft