Thin walled spark plug sockets are required for access in many modern engines. Sizes: 14mm (O.D 18mm), 16mm (O.D. 20.4mm), 18mm (O.D 23mm). Length 63mm x 12 point (Bi-Hex) profile. 3/8" square drive. Manufactured from Chrome Vanadium with rubber inserts. Note: Packaging may vary.