Features: Kincrome’s range of impact sockets are manufactured from Chrome Molybdenum (Cr-Mo) and feature a black phosphate finish for superior corrosion protection, laser etching for easy drive size identification and Peripheral Drive technology. Peripheral Drive provides greater torque by relocation the load to the flat sides of a fastener, this allows for greater surface area contact and prevents "rounding off" of fasteners. EVA Tray for storage 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.