Features and Benefits: 12 PC. 3/8'' DR. MAGNETIC SPARK PLUG MASTER SET; Versatile set includes different socket types and configurations:; metric, SAE, 6-point, 12-point, standard length, extra deep, thin wall, universal joint and dual drive; Ideal for use in a variety of domestic and imported cars; Equipped with magnetic ring inserts to hold spark plugs in place; Spring loaded universal joint design makes it much easier to handle and place sockets on spark plugs located in hard to reach or confined spaces, while preventing the joint from becoming loose; 6-point sockets are single knurled and 12-point socket is double knurled for easy identification; Knurling on socket body provides grip when turning by hand; Dual drive feature enables you to turn sockets using either a 3/8?? dr. ratchet for the internal drive or a wrench for the external drive12 PC. 3/8'' DR. MAGNETIC SPARK PLUG MASTER SET