A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6110-00-199-5451
NSN 5950-01-438-7330
NSN 6105-01-446-6527
NSN 5920-01-048-6907
NSN 6105-01-321-7063
NSN 5985-00-148-7316
NSN 6645-01-436-9702
NSN 6130-00-035-3898
NSN 5835-00-466-3075
NSN 5998-01-593-5368
NSN 6685-00-982-6057
NSN 2925-00-845-1480