A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5990-01-649-4647
NSN 6105-01-506-5260
NSN 6240-01-412-7803
NSN 5925-00-622-2294
NSN 5960-00-258-9292
NSN 5998-01-285-3890
NSN 6620-00-910-5464
NSN 7035-01-596-3411
NSN 5985-01-261-5384
NSN 5835-01-592-2350
NSN 6105-01-519-4223
NSN 5945-01-516-5525