Babolat Andy Roddick Pure Drive Racquet Constructed with a graphite and Kevlar blend to help create a lightweight, yet stable racquet, Babolat's Andy Roddick Pure Drive has a Cortex system that filters out vibrations in order to enhance the feel of the ball. THe racquet also features Woofer technology, a patented innovation by Babolat which makes the frame and the strings interact when striking the ball. A tennis racquet is a frame with strings. The frame is basically static and holds the driving force of the racquet - the strings - in place. Woofer is the first technology which permits all of the strings to work together to their full potential when striking the ball, thanks to two functions: piston and pulley. Piston enables larger, uniformed string bed deformation on impact for shock absorption and the pulley function acts like a suspension system to dampen vibrations. Features: Delivers 10% more power than conventional racquets, and ensures that the strings retain their