A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-423-1051
NSN 5985-01-089-5799
NSN 5925-01-350-7136
NSN 6130-01-442-8295
NSN 5920-01-088-8312
NSN 5920-01-378-3869
NSN 5998-00-225-8522
NSN 6685-00-143-7281
NSN 5835-01-070-3745
NSN 6610-01-440-0604
NSN 6145-00-295-2887
NSN 6105-01-442-3465