A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-00-882-4124
NSN 5935-00-325-8429
NSN 6685-01-605-5402
NSN 5975-01-233-5736
NSN 6145-00-215-4994
NSN 5985-01-381-2563
NSN 5915-01-333-4749
NSN 5990-00-900-4459
NSN 5915-01-575-3695
NSN 6150-00-229-5822
NSN 6145-00-521-0001
NSN 7035-01-441-9509