This is a great sounding overdrive/distortion for bass using a single BJT transistor. It's in a tiny 1590A enclosure but it has a HUGE tone . The controls consist of a gain, output (volume) and tone. It can go from almost 100% clean to to a heavy overdrive/distortion. I am only going to be offering 10 builds of them for sale so get yours before they're sold out. Check out the quick soundclip of it below.............