This overdrive pedal centers around a preamp that adjusts the core of the sound! It features input and output level adjustments, as well as clean boost, high-cut, low-cut, and harmonics boost functions. There are two types of PREDRIVE: studio and handwired, and this is the handwired model. It's a rare pedal, but you can listen to the sound on YouTube, etc. The handwired model operates on an 18v power supply. It looks scratched, but it's the original aged processing. Operation has been confirmed and there are no problems. PETTYJOHN Electronics PreDrive PETTYJOHN_PREDRIVE_0204