Plugs directly into your guitar—a great-sounding headphone bass amp that gives you serious sound fast. AUX in jack lets you jam along with your CD/MP3 player. 100% analog circuit faithfully simulates the response of the original amps. Up to 15 hours of battery life with two Alkaline AAA batteries. Quick and easy setup! Just connect amPlug to your guitar and enjoy serious sound. With its completely analog design, great care was also taken with amPlug's gain circuitry.