A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-467-2668
NSN 5930-01-236-5887
NSN 5950-01-142-9087
NSN 6685-01-399-8584
NSN 6650-00-195-7519
NSN 5910-00-436-6821
NSN 5998-01-095-3637
NSN 5835-01-149-2442
NSN 5990-01-645-2592
NSN 6645-01-231-2432
NSN 5999-01-317-6612
NSN 5996-00-857-3077