Designed to meet the needs of modern players who want to fully retain natural guitar and amplifier tones Truly Buffered continuous signal Discreet ,Point to Point hand wired boards Full size Pots American construction and Quality The Dual-Harmonic boost power: single 9 volt 2.1 mm w/center neg DC. 2.1mm Looking directly at the Dual harmonic Boost Guitar input is far right Amp out is far left on the rear of the unit.DC power is center input. First section on the right (purple led) is the original 'Harmonic boost' found in the Soap Box. with a single 'level control and an additional master tone control as the use of this section is best suited for adding chime and crispness to darker guitars or just adding more articulation and harmonic content to solo's. The master Drive/ Boost section on the left(green led) can push your amps range from a subtle warm boost to a big, nasty pre -amp drive while truly retaining all of the character,definition and voicing of Your amplifier at any volume settings ! Any combination of both sections together yield some of the most complex, tonefull,musical and inspiring textures available in one unit.