here are nine ,9 ,  old black radio ,broadcast , amplifier , mixer KNOBS most likly all RCA brand.

the skirt on the small knobs measure 1-1/16 inch diameter.

the skirt on the 6 larger knobs measure 1-1/2 inch diameter.

some have an allen screw and some have a sloted screw.

one smaller knob is missing the screw.

all screws turn freeley

two of the smaller knobs and two of the larger knobs with flat sides have the "MIC" imprint on the bottom.

two of the larger round knobs have the "VIC" imprint on the bottom.

the small knob with no markings uses only one screw while the two small knobs with the "MIC" imprint uses two screws each.

since they came from large piles of knobs i have no way to tell what they came from.

I ALSO HAVE MANY OTHER STANCOR , THORDARSON , UTC and other  TRANSFORMERS .