The HOG 30 is a recharging amplifier, it is perfect for outdoors speaking engagements, practice sessions and for playing loud clean sounds virtually anywhere. While it was originally designed for use with electric guitars & keyboards, it will work very well with any electric instrument and /or microphones, and can amplify radios, tape players or audio cd players. You can connect multiplies of these units together in series for an even better sound. You won't believe the amount of sound these amplifiers produce! And for a price everyone can afford!