A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5855-01-258-7557
NSN 2925-01-620-9673
NSN 6220-00-358-9580
NSN 5910-01-535-1028
NSN 6240-01-641-2666
NSN 6685-00-276-9889
NSN 6645-01-503-6337
NSN 5925-00-393-2410
NSN 6620-01-413-1951
NSN 2925-01-458-5808
NSN 6220-01-163-8775
NSN 5905-00-451-5740