A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5965-00-964-1756
NSN 7035-00-043-1325
NSN 5915-00-477-9446
NSN 5905-01-615-5532
NSN 5835-01-090-0784
NSN 6220-01-306-8230
NSN 6320-01-315-2982
NSN 5950-00-248-6921
NSN 5835-01-366-5906
NSN 2925-01-633-4048
NSN 5855-00-481-0019
NSN 5925-00-013-9423