A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5905-00-732-2731
NSN 5960-01-462-6267
NSN 6110-01-554-0544
NSN 6105-01-383-2139
NSN 6620-01-061-3497
NSN 5835-01-462-5983
NSN 6240-01-510-3050
NSN 6105-01-067-6702
NSN 6620-00-555-3992
NSN 5998-00-248-6943
NSN 6145-01-114-8001
NSN 6620-01-149-0700