DIN 9250 stainless steel safety washers are conical-shaped, double-sided serrated locking elements designed to prevent bolt/nut loosening from vibrations, shock, or thermal expansion.
Using A2/304 or A4/316 stainless steel, they provide high corrosion resistance and reliable force-locking through radial ribs that bite into mating
These are often called Schnorr washers
