A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-444-5111
NSN 5999-01-133-6850
NSN 6110-00-228-8570
NSN 5975-00-631-5817
NSN 6620-01-519-2628
NSN 5960-00-998-4324
NSN 5835-00-611-0607
NSN 5855-00-189-6066
NSN 6620-01-568-2555
NSN 5910-01-246-9819
NSN 6220-00-625-8554
NSN 6135-01-362-4256