Gain knob adjusts total output volume when micro amp is engaged

Buy at www.musicianscart.com Dunlop MXR M133 Micro Amp Guitar Effects Pedal,Footswitch toggles amp on/bypass,Red LED indicates “on”,Gain knob adjusts total output volume when micro amp is engaged,Power: Single 9-volt battery or Dunlop ECB-003 AC adapter (sold separately),Tough,compact metal enclosure.