JOYO mini pocket guitar amp amplifier tube drive is easy to use, catch your inspiration anytime. Made of ABS plastic. Power: AAA battery, 2 pieces (included). Small enough to clip to your belt or hang from guitar body. 3.5 mm Mp3 input jack and 3.5 mm earphone input jack. Plug your CD or MP3 player in and play along. Power indicator. Available black and silver in colour.