It is what the picture says, small enough to fit in many places. The OD is a bit difficult to control, but I don't really care about that. It is so light that if you move the plugged-in guitar cable while connected to the amp, you may crash it, so be careful. It needs grounding, because it gets noisy when I bring my hand close to it and if I move my hands off the guitar. Maybe it's just like that because I have it plugged in to an adapter, I have not tried it on a battery yet. I am still going to use it when travelling.