Andoer Joyo I-plug Electric Guitar Mini Headphone Amp Amplifier Built-in Overdrive Effect Connecting to iPhone Samsung iOS/Android/Window Compact Portable Compact and light-weight design, not bigger than a hand of the adults. Built-in distortion effect. Designed with 3 adjuster: Volume, tone, gain. Designed with a clip on the back, easy to fix on belt, pocket or anywhere else. Powered by two AAA 1.5V batteries (not included).