A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6320-01-225-9963
NSN 5935-01-225-1417
NSN 5855-01-634-0259
NSN 5910-00-801-6130
NSN 5965-01-190-7391
NSN 5835-01-227-4752
NSN 6650-00-077-0638
NSN 6620-01-530-7538
NSN 5998-01-227-7690
NSN 5998-00-705-0222
NSN 5965-01-522-7706
NSN 5895-01-386-3049