DIN 6797 A External Tooth Lock Washers
DIN 6797 A External Tooth Lock Washers have twisted prong teeth on the largest radius, which results in superior torsional resistance, and are the preferred tooth-type lock washer when the greatest locking ability is desired. However, they are primarily suited for large diameter heads, like pan, because the teeth must contact both the fastener and mating surface; the teeth and surface indentations they create will likely be visible. Spring steel with a zinc plated and plain finish (unplated and susceptible to rust), along with stainless steel, can be supplied. Size is nominal hole size, so select a washer that matches the screw size (if you have an M6 screw, select an M6 washer for example). They may be listed as DIN 6797 Type A.