HEAD's unique frame design delivers optimal stiffness and a solid feel thanks to the innovative IGS2 (Inner Grommet System) and graphene, the world's strongest and lightest material. The 2016-2017 GrapheneXT Radical Series racquets feature graphene integrated into the racquet shaft, making them more stable and allowing for an optimized redistribution of weight. Used by several top men and women touring pros, the HEAD Graphene Radical Racquet Series is the most technologically advanced racquets HEAD has ever designed.