... . Surface treat: white zinc (CR+3), yellow Zinc(CR+6). M8 Rivet Nutwe use cold forged technique, not only save materials ... according to customer's drawing.specification:M3 ,M4 ,M5, M6, M8 ,M10 ,M12, inch: 1/2,3/8,1/4,5 ... . Surface treat: white zinc (CR+3), yellow Zinc(CR+6). M8 flat head round Rivet Nut