Introducing a new style of amplifying audio from your MP3, phone or laptop with this Rock Out 2 Rechargable Speaker by Goal Zero. It plays 20 hours of non-stop music on one full charge without draining your music device’s battery. Since the speaker itself has easier control features, you can safely put your music speaker inside the box and zip it away thus providing an additional protective cover for your music players. For charging the speaker, you can either choose the conventional USB port or use the Nomad 7 Solar Panel if you’re carrying it outside on a bright sunny day. An excellent way to keep music by your side without losing your smartphone or MP3 player’s charge by any way.