A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-019-1983
NSN 6130-01-541-1560
NSN 5950-01-419-0747
NSN 5975-01-634-0678
NSN 6645-01-023-8724
NSN 5915-00-973-6397
NSN 6650-00-155-8431
NSN 5935-01-071-4640
NSN 5945-01-421-1808
NSN 6130-00-081-4317
NSN 5965-00-875-3560
NSN 6320-00-857-4073