Like a tube amplifier, it responds well to the guitar's volume and touch, and you can control the sound from a bell-like clean to the saturated overdrive sound of a British big stack amplifier by adjusting the picking strength and volume.・VOLUME sets output level・DRIVE knob knob sets overdrive intensity・TONE knob adjusts tone from dark to bright・FOOTSWITCH toggles effect on / bypass (blue LED indicates on) Input Impedance: 500kΩ Output Impedance: 5kΩ Noise Floor: -87 dBV Bypass: True Relay Current Draw: 15 mA Power Supply: DC 9 volts [To customers who previously purchased the WHE204i] Unlike our 40th anniversary model, the WHE204i, the WM31 is a regular lineup model that is produced entirely in-house by Jim Dunlop. Although the circuit board design values are roughly the same, the WHE204i is a commemorative model assembled and shipped by George himself in his own workshop. Thank you for your understanding.