This kind of spring washer is vskD washer. It is made according to the standard DIN127,DIN128 , we can produce from the size M3-M48, the Material of it on the pic is Stainless steel, there is striation on the surface of the washer. The material can be stainless lteel, steel or copper. We also can make DIN128, DIN7980, ASME, JIS and other standards or NON standards.