A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-01-520-6110
NSN 7035-01-391-9858
NSN 5855-01-131-9336
NSN 6105-00-940-0792
NSN 5925-00-871-6497
NSN 5990-01-218-8976
NSN 6105-01-281-3219
NSN 5975-00-467-8777
NSN 6145-00-850-4906
NSN 6685-01-295-2382
NSN 6145-01-124-0617
NSN 6685-01-204-9005