Large openings on the six corners of the opening create a floating action that allows the socket to slip quickly and easily onto the nut or bolt. Ideal for compensating for imperfect alignment between the tool and fastener. Not generally recommended for impact use. These sockets are identified with a SF- prefix.

SF-21MM15 Apex 21mm Surface Drive Metric Standard Socket, 1/2” Square Drive from Apex Fastener Tools formally Cooper Tools, have hex tolerances that are on average 48% tighter than DIN and 35% tighter than ANSI requirements. SF-21MM15 Apex 21mm Surface Drive Metric Standard Socket, 1/2” Square Drive provide an exact, sure fit every time. Apex impact sockets provide the tightest tolerances for straightness and concentricity available.

High strength fasteners in the aviation industry or high performance automotive field often require the use of an impact wrench or impact driver to deliver the amount of torque required to tighten or loosen them. Apex impact sockets are designed and manufactured for high impact use. SF-21MM15 Apex 21mm Surface Drive Metric Standard Socket, 1/2” Square Drive are made from stronger alloy steel than the average impact socket.