A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5945-00-154-2963
NSN 5920-01-088-0707
NSN 5975-01-492-6386
NSN 5935-00-923-7119
NSN 5895-01-131-4222
NSN 5996-00-373-9001
NSN 6145-01-207-2281
NSN 7035-01-068-4175
NSN 2925-00-155-2100
NSN 4140-01-416-7599
NSN 6320-01-495-0512
NSN 6685-01-550-8554