Heavy Nut 1)Standard:DIN,ANSI,ISO, 2)Materials:carbonsteel. Stainless steel . ... steel . 3)Grade:class 4.8 6.8 8. Heavy Nut Size 1/2"-3" Specification ASTM A193 B7/B16/B8M ... .21.1, DIN125, DIN9021, DIN 127, DIN 7980.Finishing (Surface): Self Color, Xylan. Black ,Teflon Coating (PTFE) Black, White or Blueness ...