M12 Hex Nut - A2 Grade A2 stainless steel has good resistance to corrosion except in severe industrial and Marine Condition. Use A4 in a marine environment. Where: e = point to point m = thickness s = across flats d = Thread e - 21.10 mm (min) m - 9.64 mm (min) s - 19 mm d - M12 Thread Pitch - 1.75 mm DIN934