Loud box mini charge battery-powered acoustic instrument amplifier the loud box mini charge is a portable, battery-powered amplifier designed to faithfully reproduce the sound of acoustic instruments and a diverse assortment of vocal or recorded accompaniments. A powerful, rechargeable battery, combined with unique power management circuitry, is specifically designed to maximize output levels and playing time. With the addition of Bluetooth wireless connectivity, you can now easily and neatly add backing tracks or other accompaniment to your performances, Jams, or wherever your loud box mini charge takes you and your music.