A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-01-025-6764
NSN 6650-01-344-6550
NSN 5965-01-633-8849
NSN 5960-01-170-4057
NSN 7035-00-436-1229
NSN 5945-01-361-8768
NSN 5960-01-177-7406
NSN 5925-01-250-1035
NSN 6620-00-067-4946
NSN 6105-01-431-4409
NSN 5905-01-440-0046
NSN 7035-01-429-7954