A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-01-096-6803
NSN 6645-01-361-8052
NSN 5855-00-221-9435
NSN 5855-01-003-7102
NSN 5925-00-468-2757
NSN 5999-00-453-5346
NSN 6320-00-937-5625
NSN 6320-00-036-3688
NSN 5998-00-530-7185
NSN 6685-01-467-2493
NSN 5910-01-568-6862
NSN 5950-00-359-3846