A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-142-6456
NSN 6240-00-143-7513
NSN 5835-00-025-9951
NSN 6135-01-445-6589
NSN 6110-01-277-9324
NSN 5965-00-222-7394
NSN 5835-01-325-5677
NSN 6685-00-890-8410
NSN 7035-01-574-6363
NSN 6645-01-206-4888
NSN 5998-00-691-6070
NSN 6130-01-175-6010