Expert Quality, 6 point deep sockets forged from chrome vanadium steel hardened and tempered with a polished finish. Each socket has a knurled ring for extra grip. Fitted with rubber insert for spark plug insulator protection and retention. Display packed. Contents: 1 x 10mm thread (16mm socket), 1 x 12mm thread (18mm socket), 1 x 14mm thread (21mm socket)