A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-00-469-8534
NSN 5895-00-432-2413
NSN 6650-00-834-9062
NSN 5945-01-398-1831
NSN 6645-01-200-5289
NSN 5950-01-537-7142
NSN 5990-00-689-5736
NSN 2925-01-197-7864
NSN 5998-00-324-0878
NSN 6645-01-537-1066
NSN 5835-00-689-0278
NSN 5990-01-442-3520