A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-00-959-5800
NSN 5925-01-481-3442
NSN 5905-01-132-4778
NSN 6105-01-165-3823
NSN 5998-01-542-8272
NSN 5998-00-995-2359
NSN 6645-01-076-4655
NSN 5935-00-258-9156
NSN 6130-00-148-4538
NSN 5925-00-529-0441
NSN 5960-01-522-0391
NSN 6650-01-396-3287