A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6645-01-441-2762
NSN 2925-01-208-6638
NSN 6145-01-397-6210
NSN 6650-01-278-2151
NSN 5915-01-567-5066
NSN 5910-00-479-9931
NSN 6110-01-400-4207
NSN 5998-01-304-6447
NSN 6620-01-032-3937
NSN 5905-01-313-2343
NSN 5998-00-594-0357
NSN 5920-01-110-7312