Electro-Harmonix Bass Big Muff Distortion Pedal On/Off switchControls for Volume, Tone, and SustainDual outputsMini Switch for Bass BoostRugged metal chassisRuns on 9 volt battery (best with Polaroid 9 Volt batteries) or optional AC Adapter (sold separately). The Bass Big Muff Pi Pedal features controls for volume, tone, sustain, dual outputs (effect and dry for recording), and a mini switch for bass boost The Electro-Harmonix Bass Big Muff Pi Distortion Pedal is powered by a single 9-volt battery or optional AC power supply (sold separately)