M4 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 Thread Pitch - 0.7 mm e - 7.66 mm (min) m - 2.9 mm (min) s - 7 d - M4 DIN 934