A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-00-872-5683
NSN 5895-01-420-6926
NSN 6145-01-173-4319
NSN 5930-01-398-9576
NSN 5950-01-544-6297
NSN 5910-00-332-1140
NSN 6620-01-087-2354
NSN 5915-01-451-8975
NSN 6620-00-148-9613
NSN 5999-00-343-3724
NSN 6130-00-493-6243
NSN 6145-01-238-9297