A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-00-555-3251
NSN 2925-01-041-8201
NSN 5990-01-605-9026
NSN 5920-00-243-8181
NSN 6220-01-616-4492
NSN 5999-01-160-4878
NSN 6135-01-461-2915
NSN 6145-01-439-9548
NSN 4140-01-356-5614
NSN 5950-00-931-0263
NSN 5935-01-633-5263
NSN 5998-01-422-1516