A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5905-01-175-3533
NSN 5985-01-574-0012
NSN 6110-00-116-5514
NSN 6130-01-387-5490
NSN 5985-01-392-2811
NSN 6620-01-194-1081
NSN 6685-01-507-4342
NSN 6650-00-330-0108
NSN 6105-01-286-0576
NSN 6610-00-674-6073
NSN 5905-01-315-2691
NSN 6145-00-089-0547