The Thunderdrive is an overdrive pedal kit that will provide a signal boost at low gain settings and it's own distortion at maximum gain settings. You can use it to push your preamp into overdrive or as a source of smooth distortion.
Using point to point wiring and easy to follow instructions you can have a working overdrive pedal in a matter of hours.
All you need to provide is solder and a soldering iron. Uses 9 volt battery which is not included.