This Mini Mobile Speaker for iPod iPhone Computer Laptop with a very small footprint, very ideal for travel and mobility, this set of speakers speaks louder than other speakers of bigger sizes. Give it a twist and the top portion expands, giving you extra air space which brings out the bass. You'd have to hear it to believe it. For speakers this size, it sure packs a punch. With built in lithium batteries, you can have hours and hours of listening. And with the built-in retractable audio and charge cables, there are no extra cables to bring around and no cable mess. When you need to charge your speaker, just pull the charge cable out, and connect it to a mini USB, or use the included USB charge adapter to connect to a USB port. The speakers come in dual speaker configuration with stereo sound.