A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-01-236-6514
NSN 2925-01-448-2880
NSN 4140-01-459-3136
NSN 6220-01-441-2249
NSN 6650-01-417-8143
NSN 6685-00-265-7530
NSN 5950-01-435-5478
NSN 6150-01-600-0893
NSN 6145-01-195-7329
NSN 6130-01-426-8841
NSN 6645-01-440-5500
NSN 5950-00-144-4139