A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-01-632-5501
NSN 6135-00-998-5884
NSN 5930-01-106-2922
NSN 5905-01-644-9805
NSN 5835-01-099-1514
NSN 2925-00-155-2100
NSN 6610-00-406-8544
NSN 5996-01-321-1559
NSN 6685-00-893-9020
NSN 6220-01-598-8868
NSN 6220-00-266-8222
NSN 5965-01-373-8858