The Blues Pro has an interesting story. When I first started work on the Blue Boy overdrive, I worked on the design till i got to a point where I was happy with it. So I went out and had a whole bunch of PCBs made up. What I didn't count on was changing my mind,... which I did. I was then not able to use the PCBs. So, what I decided to try to recoup some of the money I'd pumped into the PCBs by making these pedals up, putting them in a bare aluminium case, and selling them at cost. I called this pedal the 'Blues Prototype'. What I didn't count on was just how popular these pedal were. They are still on the second hand market today, in most cases getting considerably more than what was paid for them.