1 Meg Audio Taper Amplifier Potentiometer With Piggybacked On-Off Switch For Vintage Guitar Amplifiers, Radios Etc. Good quality pot for building Fender Champ clones and for repairs to similar vintage guitar amps that piggyback a rotary AC On-Off switch on the back of the volume control. OK construction; not as rugged as the original Stackpole part but nicer than I expected for the price. Nickel plated metal case. Solid aluminum shaft for standard set screw knobs measures .235" diameter (just under 6mm). I tried an old Dakaware set screw knob and it fit fine. Knobs with an approx. 6mm opening designed for import solid shaft pots will also fit. 11mm mounting nut and beauty washer are included.