50/100X M2.5 M3 M4 M5 M6 M8 M10 M12 GB862.1 DIN6798A A2 304 Stainless Steel External Toothed Serrated Lock Washer Gasket
https://www.vogueparade.com/shopping/EN/42/1/1005003517704704/50100x-m25-m3-m4-m5-m6-m8-m10-m12-gb8621-din6798a-a2-304-stainless-steel-external-toothed-serrated-lock-washer-gasket//