Head continues d3o technology in the Head YouTek line, and is a "smart" material in that it behaves differently under varying vital loading or impact. Integrated in the frame lay-up and positioned in the shaft area (where the racquet flexes the most), d3o seeks to help players maximize performance on all shots. High speed impacts lock d3o together within nanoseconds at the molecular level, stiffening the frame to provide maximum power. Conversely, on slower speed impacts, the d3o molecules absorb the impact providing softer touch for better feel. The IG Speed, IG Radical, and IG Prestige racquets also use lightweight Innegra fiber for enhanced feel. DuPont Teflon grommet system that reduces friction. Less friction means maintaining more of the strings energy, and a resulting slight increase in power.