The potentiometer has a 250k ohm resistance suitable for the audio path of passive instruments only. Behind the jack area under the footplate is a taper switch, which provides the user two distinct volume swell rates. Attached to the footplate is an on/off switch connected to the jack labeled "Switch". This is an isolated circuit and may be used for controlling other gear in your system like amp channel switching, effects bypass, etc. Overall Volume Pedal dimensions: 4" W x 11" L x 2 3/4" H.