This silicon fuzz has a rich subby ripping texture with aggressive midrange and plenty of volume. Your Fuzzolo has two knobs, one controlling Volume and the other controlling Pulse Width, which sweeps between square wave and a narrow/wide pulse shape. Connect a music equipment power supply of 9VDC, center negative, to the power jack for use. There is no battery in your Fuzzolo. For use with Bass or active pickups, open the unit’s bottom lid and move the black jumper from P to A. For use with Guitar or passive pickups on quieter instruments, make sure the jumper is on P. The “P” appears backwards on the circuit board. We don’t know why.