CT-907 Magnetic Spark Plug Socket (Formerly CT-430) A companion tool to the Champion Plug-Master and other 3/8in./0.95cm square drive wrench handles. Especially designed for shielded aviation spark plugs. Built-in permanent Alnico magnet holds plugs firmly - practically eliminates dropped plugs. Length: 3 1/2 in./8.9cm - chrome finish; 3/8 in./0.95cm - square drive; 7/8 in./2.2cm - deep hex. Weight 8 1/2 oz./241g. Packed individually.