6-point hex socket for maximum torque transfer to the face of the fastener. Precision cold-forged, hardened and tempered chrome vanadium steel. Fully polished and nickel chrome-plated for durable corrosion resistance. Chamfered ends and thin walls for positive location on fastener. Contents: 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16" and 3/4" AF.