M3 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 - 6.01 mm (min) m - 2.15 mm (min) s - 5.5 d - M3 Thread Pitch - 0.5 mm DIN934