Kincromes range of Hex impact sockets are manufactured from Chrome Molybdenum (Cr-Mo) and feature a black phosphate finish for superior corrosion protection and laser etching for easy drive size identification. Chrome Molybdenum is an industrial grade material designed for impact and extreme torque applications. Hex Impact sockets are designed to withstand the high torque and force associated with impact tools in repetitive application and can be used on stubborn fasteners. IMPORTANT:Only Impact Sockets should be used on air or electrically operated power tools. NEVER use silver Chrome Vanadium Steel (Cr-V) Sockets which can shatter and cause personal injury.