A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-01-444-0812
NSN 5930-01-506-5314
NSN 5910-01-310-9716
NSN 5910-01-382-1663
NSN 5910-01-053-5099
NSN 5945-01-445-6081
NSN 6130-01-587-4788
NSN 5960-01-142-1995
NSN 6645-00-542-1734
NSN 5855-00-797-8217
NSN 5975-01-511-2868
NSN 6220-01-545-3267