Black Friday Special! Buy 1 Set of Tourna Grit Tennis String and Get 1 Set Free!! (Valid Nov 23st to Nov 26th Only) Does your game have Grit? Tourna introduces an innovative new string made with Nano Technology, called Tourna Grit. By combining carbon fiber nano particles with advanced co-poly materials, it leaves the string feeling ??gritty?? which grabs the ball and imparts massive spin. Tiny strings of graphite less than 10,000 thinner than human hair, yet 100x stronger than steel and 80% lighter make for a very durable string, yet one that is extremely elastic and lively, full of feel and pop. Tourna Tennis String GRIT-18-S-B1G1