HI-TORQ® Metric Deep Impact Socket, 3/8" Sq. Dr., 20mm - Draper 20177, This Draper Hi-TORQ® 6-point impact socket is forged from hardened chrome molybdenum steel.Black phosphate finish for corrosion protection.For use with electric or pneumatic impact wrenches with a 3/8" drive. Draper 20177 HI-TORQ® Metric Deep Impact Socket, 3/8" Sq. Dr., 21mm