... .surface of screw:zp,hdg,black,oxide self tapping screw1.various kinds of self tapping screw available.2.high quality competive price ... steel,alloy steel,copper etc...4.surface treatment of self tapping screw:Passivation,Chromium-Plating,Black, Zinc-Plating or according ... DIN and special spec according requirement.6.packing of self tapping screw:general export packing poly bag cartons or according ...