One of the biggest pains of an electric guitar is the need to hook it up to an amp to hear actual electric guitar sound. That’s not a problem with the milli-AMP! The milli-AMP uses a bridged ML386N-3 amplifier circuit to produce in the neighborhood of two watts output power. It runs of a rechargeable 9 volt battery that provides an hour of full volume play per charge. At two watts, the milli-AMP is more powerful than any commercially available amp (that I know of) of its size; its size being a very pocketable 2.25 by 3.5 by 1 inches (roughly). Volume is controlled by the volume pot on the guitar, and controls distortion as well.