The Electro-Harmonix Flatiron is a fuzz distortion pedal intended for electric guitarists. The pedal sports a classic op-amp design to give you both warm, rounded distortion and high-octane fuzz. Set the pedal to mild values to preserve a moderately clean tone with low-level saturation, or crank the Drive dial to secure a hefty, classic 1970s fuzz. Use the Drive knob to dictate the amount of input gain in the circuit. The Filter knob introduces a low-pass filter for curtailing the highs, which can sometimes be over-emphasized by fuzz distortion. As you turn this knob clockwise, the center-frequency increases, letting you introduce more high-end into the circuit. The Volume knob controls the output level of the pedal. The Flatiron employs True Bypass circuitry on the Bypass/Engage footswitch, so that your tone remains pristine when the pedal is disengaged. A 1/4" instrument input and 1/4" instrument output are provided for your guitar. Use the supplied 9V battery to power the pedal on stage, or use a separately available EHX9.6VDC-200mA power supply.