Silverline Impact Socket 1/2" Drive 6pt Metric 21mm

Amazon

Impact 6-point hex sockets specifically forged for use on powered impact tools Precision cold-forged, hardened and tempered chrome vanadium steel Clear, laser-etched sizes and industrial phosphate-coated for corrosion resistance Thick walls provide strength and durability for repetitive high torques Side wall hole for ball or pin locking to the tool, Weight: 0.18298367746 Pounds, Manufacturer: Silverline

ManoMano

Impact 6-point hex sockets specifically forged for use on powered impact tools. Precision cold-forged, hardened and tempered chrome vanadium steel. Clear, laser-etched sizes and industrial phosphate-coated for tough corrosion resistance. Thick walls provide strength and durability for repetitive high torques. Side wall hole for ball or pin locking to the tool. - 21mm

Electrical World

Impact 6-point hex sockets specifically forged for use on powered impact tools. Precision cold-forged, hardened and tempered chrome vanadium steel. Clear, laser-etched sizes and industrial phosphate-coated for tough corrosion resistance. Thick walls provide strength and durability for repetitive high torques. Side wall hole for ball or pin locking to the tool.