... of screw:zp,hdg,black,oxide 4.rohs iso certification flat head self tapping screw1.various kinds of self tapping screw available ... .MaterialIron/Low carbon steel.stainless steel.brass,alloy steelSurfaceHot dip galvanized,,zinc plated,black,oxide,Passivation,Chromium-PlatingColorNatural color,blue/white ...