Stanley Proto J7214PF 3/8-Inch Drive High Strength Magnetic Power Socket, 7/16-Inch, 6 Point ProtoGrip Magnetic Sockets use high-strength magnets made from a rare earth magnet alloy/nylon blend ProtoGrip Magnetic Sockets require no bushings to hold the magnet in place Designed to easily pick up heavy fasteners and hold them tightly during use Strong magnetic hold helps increase efficiency when installing fasteners in awkward or hard-to-reach locations Power sockets with high surface hardness are used in high-speed assembly operations. Ideal for nut runners