A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-216-5479
NSN 5920-01-418-1821
NSN 2925-01-442-4171
NSN 5950-01-538-9073
NSN 5930-00-060-4694
NSN 5990-01-651-6364
NSN 4140-01-492-3791
NSN 2925-01-331-5039
NSN 6105-01-523-5210
NSN 6105-00-153-0238
NSN 6105-00-804-9485
NSN 6645-01-426-8621