A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-893-0859
NSN 6610-00-010-9714
NSN 5925-00-608-0973
NSN 5960-00-274-4188
NSN 5996-01-024-8898
NSN 5920-01-479-8960
NSN 5999-01-086-1018
NSN 5998-01-054-3344
NSN 5915-00-057-3779
NSN 5925-01-417-9203
NSN 6145-00-090-5411
NSN 5835-00-936-8753