A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-344-2442
NSN 5930-01-255-4490
NSN 5835-01-618-7621
NSN 5975-01-137-6471
NSN 6220-01-504-6494
NSN 6145-00-738-5601
NSN 5895-00-262-4331
NSN 5930-01-417-3148
NSN 5998-01-398-4230
NSN 2925-01-483-6248
NSN 6105-01-340-3107
NSN 5965-01-595-9498