This Draper deep socket set is designed for fastening low-lying screws and protruding threaded rods. It includes ten 1/2" square drive sockets in metric sizes: 10, 12, 13, 14, 15, 17, 19, 22, 24, and 27mm. The sockets are forged from chrome-vanadium steel, then hardened, tempered, and chemically blacked for superior impact strength, toughness, durability, and corrosion protection. They are suitable for use with air and electric powered wrenches. A hole for an accessory spring-loaded ball ensures secure fitting with power tool drives. The set comes supplied in a plastic storage case for safe and easy transportation. Important Safety Note: Only use impact sockets and accessories with air or electric powered wrenches. Never use silver chrome vanadium steel sockets, as they can shatter and cause personal injury.