This unique and patented design works on 2004ƒ??newer Ford F-150 pickup trucks with 5.4L 3-valve Triton V-8 engines. ƒ?› Socket end is 9/16". Soft rubber insert holds and protects spark plug during removal and installation. ƒ?› Extension is part of the socket. Easily fits down spark plug tube in cylinder head. ƒ?› Socket has 3/8" drive for use with a ratchet or breaker bar.