"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","Opti-Torque system applies torque to the fastener sides reducing corner round off","150 degree chamfer on the socket drive end for better grab constant pressure and easier use","High Visibility size markings quickly identify socket 3/8" DRIVE 21MM METRIC 12 POINT ADV UNIVERSAL IMPACT SOCKET BUP21M2V | Matco Tools