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 6320-01-652-3806
NSN 5910-01-386-6385
NSN 6110-01-097-1406
NSN 6110-01-041-3963
NSN 5990-01-344-6176
NSN 6105-01-259-6879
NSN 5950-00-760-8418
NSN 6110-01-213-0210
NSN 6645-01-199-0062
NSN 5915-01-583-6924
NSN 5960-01-133-3153
NSN 5950-01-584-7656