Ultra-Lightweight Pulley Whipple Gen 3 5 bolt pattern. Made from billet 7075-T6 aerospace grade aluminium. Stronger and harder than 6061 T6. This pulley is equipped with GripTec® a micro machining technology. This technology allows the maximum grip force to be applied to the component and belt without damaging your belt. You won't have to worry about belt slip with GripTec®. Get the maximum performance out of your supercharger.