Electro-Harmonix Little Big Muff Pi Fuzz/Distortion/Sustainer Effects PedalElectro Harmonix Little Big Muff Pi Fuzz Distortion Sustainer Effects Pedal The EHX Little Big Muff Pi is identical to our Big Muff Pi but smaller. We took the classic Big Muff circuit and simply shrunk it without any change to the sweet violin like sustaining sound. This little brother displays its heritage proudly. Key Features Tough and compact die cast chassis 9v battery included