A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-00-529-3128
NSN 6620-00-416-4131
NSN 6135-00-840-6451
NSN 5920-01-013-8594
NSN 5999-01-416-9102
NSN 5930-01-180-0439
NSN 5925-01-021-7669
NSN 5915-01-005-5126
NSN 5905-01-395-0093
NSN 6240-00-145-1536
NSN 6145-01-199-6292
NSN 5930-00-272-8876