A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 2925-00-070-4576
NSN 5930-01-558-9070
NSN 5999-01-381-3576
NSN 5975-01-574-0741
NSN 6320-01-652-3806
NSN 5999-01-296-7610
NSN 6645-01-592-0540
NSN 6110-00-663-4054
NSN 2925-00-964-7128
NSN 6620-01-078-6372
NSN 5910-01-144-9946
NSN 5999-01-222-0389