"OPTI-Torque System - torque is applied to the fastener sides and not the corners","150 degree chamfer on the socket end and chamfer on the drive end puts a better grab on the fastener for more consistent force","High visibility markings for easier identification","High performance alloy steel with state of the art heat treating process precision quench and temper","Strength wear resistance and long lasting durability","Tightly controlled manufacturing processes 1/2" DRIVE 21MM METRIC 6 POINT STUBBY IMPACT SOCKET CSP21M6V | Matco Tools