A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6220-01-274-7788
NSN 5895-01-302-9196
NSN 5835-00-302-5296
NSN 6685-01-388-2574
NSN 6135-01-347-0201
NSN 5975-01-540-0980
NSN 6240-01-439-3514
NSN 6610-01-376-9199
NSN 6220-00-050-6743
NSN 6320-01-015-9856
NSN 5965-01-344-8592
NSN 5855-01-147-4785