A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-110-9414
NSN 5915-00-445-9340
NSN 5910-01-457-9521
NSN 5855-00-482-9876
NSN 5855-00-087-3144
NSN 5905-01-581-8615
NSN 5930-01-467-1977
NSN 5985-00-138-5847
NSN 5950-00-816-4303
NSN 5999-00-343-6770
NSN 6220-01-430-0171
NSN 5920-01-056-4540