The Wilson Control Duo Hybrid tennis string set has a length of 12.8m (42ft), which is enough to string one racket. The string provides durability & feel typical to hybrids & guarantees controllable power. It combines the Wilson NXT Power string that delivers a great balance of power & comfort with a gut like feel & the Luxilon Alu Power string which ensures excellent durability as well as more power & feel. The NXT Power string has a gauge of 16 (1.30mm), whereas the Luxilon ALU Power comes with a diameter of 16L (1.25mm).