A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-00-269-5843
NSN 5965-01-461-2850
NSN 5998-01-507-0123
NSN 5965-01-548-0965
NSN 5905-01-324-7115
NSN 5855-01-323-5394
NSN 5975-00-228-6768
NSN 4140-00-350-9401
NSN 6150-01-464-9049
NSN 5945-01-644-0452
NSN 5895-01-557-8071
NSN 5975-01-204-7328