A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-01-485-0269
NSN 5935-01-227-6878
NSN 5930-01-194-4170
NSN 6145-00-299-6417
NSN 5895-01-569-9419
NSN 6650-00-809-1817
NSN 2925-00-105-3907
NSN 5960-01-160-3437
NSN 5930-01-412-0636
NSN 5950-01-528-2363
NSN 5835-01-336-1153
NSN 2925-01-446-0525