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 and knurled band for grip. Contents: 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 7/16" and 1/2" AF.