... , car, ship, electron and other fittings of industrial products. types: flat head ,countersunk head, round body, hex body, open end, closed end, body ... ,M4 ,M5, M6, M8 ,M10 ,M12, inch: 1/2,3/8,1/4,5/32 3/16,5/16. material: steel ... treat: white zinc (CR+3), yellow Zinc(CR+6). M8 flat head round Rivet Nut