21-piece EXO-Drive Socket Set needs LESS room for MORE torque and contact! Patented "backless" slim design and just 5-degree sweep ratcheting makes for the best Socket Set ever! They boldly go where conventional deep sockets can't. 72-tooth mechanism cranks with minimal movement. The low-profile system is closer to the fastener for more torque, better contact. Strong chrome vanadium steel, fully polished and chrome plated. 17 SAE & metric Sockets: 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4" and 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 mm; 1/4" and 3/8" drive quick-release adapters.