A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-01-579-3295
NSN 5945-00-233-5804
NSN 5920-00-009-3297
NSN 6610-01-456-9872
NSN 5985-00-755-2984
NSN 6645-00-684-3424
NSN 5915-01-126-9709
NSN 6320-00-994-0179
NSN 5965-01-111-6031
NSN 5925-01-411-6028
NSN 5996-01-575-4080
NSN 6220-01-461-2910