Comprehensive socket set includes 3/8" and 1/2" ratchet handles; 3/8" x 3" ext bar; 3/8" spin disk; 1/4" spinner handle; 1/4" octagonal sockets (1/4", 5/16", 3/8"); 1/4" M x 3/8" F adaptor; 12 x 1/4 sockets (5/32 to 1/2"), 3/8" octagonal sockets (9/16", 11/16", 3/4"); 3/8" spark plug sockets (21mm, 16mm), 3/8" metric sockets (14, 16, 17mm), 12 x 1/4" metric sockets (4 to 13mm) and 10 x 1/2" sockets (10 to 22mm).