The Loop unit is an entirely passive router therefore it is completely transparent. It allows to engage an external effect loop which includes one or more effects. A bright LED, powered with a 9V battery or a power supply (not included), indicates when the loop is engaged. With every Huge Audio router, the power is drawn only when a cable is connected to the input jack plug. Also, if no cable is connected there, the sound is electronically muted on all the amps. This means that absolutely no sound comes out of the unit then, even at maximum volume! Made in Germany.