Stanley J72903/16 Proto 3/8-inch Drive Hex Bit Impact Socket - 3/16-inch Proto Hex Bit Impact Sockets can be used on stubborn fasteners. Tight tolerances for snug fit on fastener. Hex bit impact sockets are used wherever powered drive tools are used to install or remove fasteners. Hex bit impact sockets are designed to withstand the high torque and force associated with impact tools in repetitive application. Side locking hole.