A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-01-381-1751
NSN 5905-01-234-9918
NSN 6145-01-415-3978
NSN 5930-01-448-2337
NSN 5998-01-091-3870
NSN 5915-01-620-7381
NSN 5950-01-253-6535
NSN 5905-01-500-8935
NSN 5965-01-423-8543
NSN 6620-01-553-6403
NSN 5920-01-605-8326
NSN 6145-01-449-4409