M10 A4 Grade Stainless Steel Prevailing torque nut (DIN 980) A4 grade stainless steel is also known as type 316 S31.This has a greater corrosion resistance than A2 in certain environments, and is often used for Marine applications especially when coming into direct contact with salt water. Where: e = point to point m = thickness s = across flats d = Thread Thread size - M10 e (min - 18.9 m (min) - 7.64 mm s - 17 mm Thread Pitch - 1.5 mm Prevailing torque nuts are a versatile locking nut without inserts. They can be used in similar applications to the more widely known designs from Aerotight, Nylock, Staytight and Philidas The way they work is to slightly deform the thread on application. This makes them a single use item. If you need to be able to remove the nut, you should look at aerotight instead DIN980