... dipped,nickel plating;3.Stainless Steel 304 or 316 spring nut;(Size: 1/4",3/8",5/16",1/2",M6,M8,M10,M12);4.Competitive price and ... good quality;5.OEM service available;We hope ... *ISO9001:2000 Certified galvanized spring nut(M6,M8,M10,M12,1/4",3/8",1/2",5/16")