A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-01-478-1722
NSN 5965-01-436-0390
NSN 5925-00-468-2757
NSN 6320-01-359-3921
NSN 6320-00-004-9158
NSN 5965-01-064-2107
NSN 6240-01-557-0363
NSN 5960-01-389-4055
NSN 6650-00-546-9641
NSN 6130-00-333-3559
NSN 5855-00-797-8217
NSN 5905-01-104-5320