This is a limited run of the ZVEX Tesla Reverse Fuzz Factory with 1960s NOS Czech Tesla brand germanium transistors. For fun, we have the transistors poking through the top (but close to the knobs so you won't step on them). The pedal has positive polarity and can run off a 9V battery or positive ground power supply. They have unique printed art and are hand-assembled in the USA at ZVEX HQ.