A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5945-01-186-9333
NSN 6240-01-017-7322
NSN 5835-01-504-0837
NSN 6240-00-122-6697
NSN 6610-00-382-0266
NSN 5855-01-323-5394
NSN 5855-00-990-0701
NSN 6105-01-622-4040
NSN 5925-01-488-6619
NSN 5999-01-416-0617
NSN 5905-00-136-8440
NSN 5950-01-104-7476