... head, Oval head, wafer head, Round head Recess: Phillips, Slotted, Phillips/Slotted, Hex, Slotted/Hex, Torx, Pozi, Square .Diameter: #4 - #14 Length: 3/8" - 5 ... hardness: Steel/Rockwell C28-38(after tempering) Zinc plated 3 - 5 my or 5 - 8 my. self-tapping screw