A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-00-133-2880
NSN 5920-01-607-2449
NSN 5975-01-519-4582
NSN 6110-00-602-1371
NSN 6105-01-359-3886
NSN 5999-01-044-5417
NSN 5835-01-546-2008
NSN 5985-01-089-8621
NSN 6240-01-453-7318
NSN 5965-01-056-7225
NSN 5835-00-233-6327
NSN 5915-01-571-7341