A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-01-459-7084
NSN 6685-00-959-7557
NSN 6645-01-642-3637
NSN 6135-00-299-6918
NSN 5990-00-434-9348
NSN 6320-01-082-2970
NSN 5855-01-093-8202
NSN 6320-01-608-1935
NSN 5985-01-543-5122
NSN 5910-00-935-6459
NSN 5925-00-961-5333
NSN 6220-01-431-3588