A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 2925-01-495-2690
NSN 5960-01-502-6270
NSN 5985-01-243-0495
NSN 5990-00-269-2226
NSN 5990-00-153-0055
NSN 6650-01-606-5725
NSN 5975-01-123-3283
NSN 5920-01-471-7634
NSN 6650-00-382-6080
NSN 6145-01-490-3828
NSN 6220-00-079-0178
NSN 6135-01-167-7604