Check out this used Ernie Ball VP Jr. Volume Pedal. This pedal has been tested and works. It has some wear, but looks good.
The Ernie Ball VP Jr 250k provides all the same great features as the original volume pedal while reducing your footprint by 22%. The VP 250k Jr is perfectly voiced for passive signals and features a compact, rugged design consisting of aircraft grade aluminum housing that is virtually indestructible. Directly behind the input jack under the footplate is a micro taper switch which provides the user two distinct volume swell rates.