A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-188-1831
NSN 6620-01-323-6091
NSN 5945-00-447-9950
NSN 5990-00-212-4316
NSN 5855-01-631-8782
NSN 6240-01-143-7702
NSN 5990-00-819-2615
NSN 5895-00-117-7793
NSN 5835-01-180-9441
NSN 5835-00-168-9623
NSN 5855-01-278-8922
NSN 5835-01-618-4906