Catalog calls this: metric spring - din 127b lock washer
A washer which is usually round with a centrally located hole. Its edges and two bearing surfaces are so designed that applied pressure brings into play the spring tension and/or frictional locking principle which materially resists any tendency toward turning. It may be made of one or two pieces
Classification: Spring washers and other lock washers, iron or steel
NSN 6130-01-576-8958
NSN 5945-00-905-5353
NSN 6135-01-596-3145
NSN 5835-01-130-4952
NSN 6650-01-533-1267
NSN 6610-01-076-4800
NSN 2925-01-474-3363
NSN 5835-00-794-7500
NSN 6130-00-753-7732
NSN 5910-01-173-7580
NSN 7035-01-193-2667
NSN 5985-01-634-0635