Not just a holder for your mp3 player or other small audio player, this bag functions as a speaker enabling its user to listen to and completely control the music from the outside! Turn your tunes up or down without having to access the actual device! Simply swipe or tap the graphics on the outside of the case to change the volume. Easily integrates with other speakers or headphones. A belt loop on the back allows for easy carrying. Required 2 AAA batteries (not included).