The JHS Little Black Amp Box Attenuator plugs in to the series effects loop of an amplifier and lets you control the amount of signal going to the amp's power section, this lets you really push the front end of your amp for the natural feel and tone without the ear splitting volume. High grade components keep your tone clear and pure and the passive design doesn't require any power. The JHS Little Black Amp Box is small enough to sit on top of your amp or under your pedalboard keeping it out of the way when not in use.