3 spark plug sockets : 16, 18 and 21mm. Each socket has a knurled ring for extra grip. * Spark plug socket can be turned thanks to 1/2' driver * Material : chrome vanadium steel * Fitted with rubber insert for spark plug insulator protection and retention | Article: DRAPER 1/2'' Set of 3 Spark Plug Sockets | Article: DRAPER 1/2'' Set of 3 Spark Plug Sockets