A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-00-381-8549
NSN 6130-01-252-0122
NSN 6645-00-130-8464
NSN 5920-01-584-3310
NSN 6130-01-422-8736
NSN 6650-01-444-0551
NSN 5915-01-131-6858
NSN 6645-01-180-3818
NSN 5960-01-089-8155
NSN 5895-01-366-9851
NSN 6620-00-248-6950
NSN 4140-00-090-6536