The LPB-1 Linear Power Booster from Electro-Harmonix is a preamplifier pedal that enables you to increase guitar sustain, and increase the performance of other effects, especially distortion devices. The pedal is a re-creation of the original LPB-1 introduced in 1968. It features a Boost control knob, and a true bypass footswitch. The unit runs on the included 9V battery, or an optional US9.6DC-200BI power supply.