hex washer head self drilling screw carbon steel hardened YZP Diameter from 3-6mm ... -K or -N head regular supply 3.5x15,19,25, 30 4.2x19,25, 30 40, 50 4.8x19, 25, up ... #4.2, #4.819mm to 70mm#8x3/4#8x1#8x1-1/2#8x2#10x3/4#10x1#10x1-1/2#10x2Immediately shipment! hex washer head ... self drilling screw