A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-00-269-4506
NSN 6685-01-522-6731
NSN 6620-00-188-4201
NSN 6145-00-722-9700
NSN 6645-01-633-1852
NSN 5855-00-165-3093
NSN 5975-00-200-2002
NSN 6145-01-183-2205
NSN 5855-01-502-9239
NSN 6135-01-307-6006
NSN 5925-01-575-7586
NSN 5925-00-369-7747