The Rock Out 2 Solar Rechargeable Speaker from Goal Zero makes it easier than ever to enjoy your favorite tunes on your favorite hike or backcountry ski spot. A waterproof outer shell on this rugged system helps to ensure your music player stays safe inside the fabric lined inner pocket. A DarkBass chamber provides airflow, leading to excellent sound. The Rock Out 2 is chainable with other Goal Zero Rock Out speaker systems, making it ideal for gatherings large or small. The monocrystaline solar panel charger on the back ensures that you can have tunes with you even when you're days into your trip and far from civilization. A built in USB cable power input enables easy charging when you're at home or in the car. The Rock Out 2 is Bluetooth enabled for easy wireless sound anywhere.