This is a reproduction of a pedal originally produced by Masetro. It's basically a synthesizer Voltage Control Filter module and a Sample & Hold module in a stombox. This is the same circuit as the Oberhiem Voltage Control Filter. It has been modified to run on a simple 9v source with an additional effect depth control. The pedal sounds something like a random LFO controlling a low-pass filter on the incoming signal and gives a cool synthy tone  to whatever you put into it . It sounds great on all kinds of sources. Check out a clip of the original on youtube.