The Technifibre Pro Red Code Wax 16 tennis string helps players obtain more spin on the ball with a Polyethylene wax inside of the string. This wax enhancement cuts down on friction, thus making this string more durable the original Red Code string. Technifibres newest installment provides players with both durability and maximum spin to give them the best of both worlds. PU wax inside and outside of string provides 11% more durability. Official string of the ATP World Tour™.