All studs BOLTS, NUTS , Washers are available with coating as per requirement by customer. 1] Electro Zn plating: 12 to 14 microns. 2] Black Phosphating - 10 to 12 microns. 3] Hot Dip Galvanize: - 40 to 100 microns. 4] PTFEE coating - 25 microns. 5] XYLAN coating: - 25 microns. 6] Cadmium Coating: - 25 microns.