A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5895-01-423-8486
NSN 6135-00-835-7211
NSN 5915-01-122-5515
NSN 6645-00-539-1705
NSN 5930-01-559-8478
NSN 6145-00-314-6841
NSN 5910-01-095-5384
NSN 5835-01-294-5753
NSN 5910-01-245-6965
NSN 5905-01-461-8937
NSN 5895-01-009-2830
NSN 6145-01-322-0489