The Rushead Pocket Guitar AMP is an easy to use headphone amplifier for guitar and bass. Inside you'll find all the heat of the world's most famous amplifiers, each with a full range of gain adjustment. You get everything you need for clean natural tone, toasty overdrive, and even heavy metal! A special design lithium battery both powers the amp and can charge your USB devices for over five hours of continuous use. An AUX IN jack lets you play frontman to your favorite back tracks.