A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-021-9200
NSN 6320-00-908-6841
NSN 6220-01-207-7229
NSN 6240-01-160-4370
NSN 6110-01-559-2092
NSN 5985-01-129-5393
NSN 5935-00-132-2467
NSN 6240-01-586-0275
NSN 5960-01-121-4105
NSN 5895-01-519-6177
NSN 6685-01-024-7203
NSN 6150-01-302-5256