The cheapest one knob phaser money can buy, or I'll eat my hat. This teeny tiny pedal has one control for the phase, and that adjusts the speed of the phaser. Also, a little known fact, the Pepperoni has an internal trim pot which adjusts the depth of the phaser. A great sounding pedal (especially for the price), this Pepperoni Phaser is in excellent used condition. This pedal is powered by a 9 volt battery, or 9v power supply.