Electro Harmonix Bass Big Muff PI effects pedal for the bass guitar.The ultimate distortion for bass! This features a bass boost switch and was specifically designed to handle bass frequencies. It also features a dry output. This lets bass players get that great distortion that the Big Muff is known for with no loss of low end. The bass big muff features controls for volume, tone, sustain, dual outputs (effect & dry for recording), and a mini switch for bass boost. Powered by a single 9 volt battery or optional AC power supply (not included).