Welcome, you are looking at a really cool piece. This is the Pigtronix Fat Drive overdrive. This is one of the fattest, warmest, tube-sounding analog overdrive pedals out there. Multiple cascading stages allows you to dynamic tube sound from crunch to crazy leads. Rather than using a traditional tone knob, this tone knob controls a low-pass filter to fine tune the bottom end of your tone. If you want just pure, unadjusted tone, turn the knob all the way clockwise to bypass it! Like many other Pigtronix pedals, this pedal can work with a 9V power adaptor, but ships with an 18V adaptor for better headroom, clarity, and output! We are an authorized Pigtronix dealer! Don't pass this by!