A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6320-01-268-3072
NSN 6240-01-514-4184
NSN 5925-01-193-4305
NSN 5835-00-233-6327
NSN 5905-00-110-0388
NSN 5945-00-622-4804
NSN 5910-00-246-3561
NSN 5930-01-391-5093
NSN 5855-00-885-8452
NSN 5835-01-174-7700
NSN 6130-01-032-9165
NSN 2925-01-076-6128