The Rock Out 2 Solar Speaker from Goal Zero features amazing audio, a rechargeable battery, and a built-in solar panel to keep your tunes going all day long. USB ports allow connection to your favorite audio player as well as to other speakers. It's Bluetooth compatible, too! Adventure Ready & built with a weatherproof outer shell to withstand all Mother Nature can dish out (not submersible). A roomy, fabric-lined pocket keeps your gear safe inside; the attached bungee lets you strap your speaker anywhere.