The best seller of Overdrive/Booster is this Carl Martin Hot Drivin Booster 3! The natural distortion like vacuum amp is thick and clear. Warm, crisp sound creates exceptional extrusion. Special features include a booster built into the back of the distortion circuit. It is independent, so you can use it as a single booster or as a boost when you ride it. The volume can be changed to 2 levels. It has been loved by many professional guitar lists in Japan for one season. For those who want a thick, powerful drive sound.