Hope V4 Vented Disc Rotor 6-Bolt Float/Wave 203mm BlkVented rotor is constructed of three pieces and uses internal fins to allow air to flow between the two friction sides. Induced air flow significantly reduces heat build up in the rotor Vented rotor is designed specifically for V4 series brakes Fantastic and consistent braking performance in wet conditions thanks to its capability to clear the water later through its fins Dyno tests show up to 15% less heat build up compared to floating rotors