A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-00-421-4762
NSN 5930-01-430-5513
NSN 6240-01-520-6925
NSN 5935-01-424-9458
NSN 6685-00-019-0043
NSN 6620-00-500-0041
NSN 5925-01-230-5335
NSN 2925-01-455-2558
NSN 5950-01-575-2133
NSN 5965-01-613-8414
NSN 5999-01-424-2549
NSN 5960-00-584-4553