A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-975-0868
NSN 6320-01-171-3238
NSN 6685-00-703-6811
NSN 5960-01-142-1995
NSN 5999-01-232-1983
NSN 5925-01-013-8329
NSN 5915-01-463-9241
NSN 6105-00-857-3058
NSN 6650-01-105-5608
NSN 6110-00-281-3676
NSN 6145-01-097-4577
NSN 6610-01-346-8241