Our nut grip sockets are unique to Ko-ken and truly a revolutionary way of approaching this type of socket. Our fastener holds nuts and bolts in place without the use of magnets. Our system is built with a coil spring and ball bearings on opposing flats. When a nut or bolt is in the socket the ball bearings push out on 3/8 Sq. Dr. Socket 16mm Nut Grip Length 27mm