Nut ring: Nut bolt ring: Material: steel A3# Certificate: SGS Surface: galvanized, hot dip Nut ring:Nut bolt ring:Material: steel A3#Certificate: SGSSurface: galvanized, hot dipSize: 1/4", 3/8", 1/2", 5/8", 3/4", 7/8", 1", 1-1/4", 1-3/8", 1-1/2", 2" nut ring