Compressor guitar effect pedal. This compressor works with an electro-optical circuit and is commanded by two pots – Comp, which affects the amount of compression from soft compression for a more even tone up to a hard compression which squeezes the attack and boost the volume and length of the sustain. The Output pot controls the amount of volume fo the output signal and it can also work as a volume boost. This pedal´s footswitch works in True Bypass and has a blue LED signal light. DOD 280 is made of light aluminum alloy and it´s powered by a 9V battery or a power adaptor, which is not included.