If your thinking of a portable headphone amplifier then this is it. This thing sounds amazing and it's very powerful. I've got a few other portable headphone amps to compare it to and this thing outshines them all. Not only does it outshine them in sound but features as well.......this thing has separate bass and treble settings so you can tailor the sound just as you like it. The display is a nice feature which shows battery strength, volume and all your menu adjustments. It really makes a difference on all the headphones I hook to it.......it gives them all a more cleaner, crisp sound that's louder and has the bass response you can start to feel. Especially using my Monster Beats Studios :-) these things sound amazing running off this E17 amplifier. I promise you won't regret this purchase!