A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 2925-01-266-5229
NSN 5835-00-264-0946
NSN 5965-01-535-0428
NSN 5930-01-426-9130
NSN 6150-00-503-3986
NSN 6135-00-269-5843
NSN 6610-01-148-2181
NSN 5920-00-271-3217
NSN 5985-00-833-2440
NSN 5945-01-196-6030
NSN 6320-00-513-8376
NSN 6650-01-432-1830