Reduced friction and noise with graphite-treated natural rubber wiping edge Easy to install pre-mounted multi-adapter Covers: Pin arm(4. 8mm & 6. 35mm), Hook arm(9x3 & 9x4mm), Side lock(22mm), Pinch tab, Top lock(16mm & 19mm), BMW Top lock Aerodynamic wind spoiler improves airflow to create downforce and prevent blade lift-off Uniform pressure along the entire blade length applied by precision-tensioned steel spring