A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 2925-00-408-9829
NSN 5855-00-014-5008
NSN 5990-01-417-4402
NSN 5835-00-155-1379
NSN 6110-01-165-5086
NSN 6145-01-656-8445
NSN 6645-01-244-4881
NSN 6650-01-348-5448
NSN 5965-01-072-3156
NSN 7035-00-275-5604
NSN 5935-01-179-8198
NSN 5920-01-554-9804