This stereo audio amplifier kit is pre built. It's ideal for product design projects. It uses a NJM2073D audio amplifier IC which can output 1W per channel. The kit is supplied with two speakers and a pre-made 3.5mm jack plug. It works nicely off a PP3 battery (9V), or runs off any voltage from 2 to 15 volt. All that is required is to solder the jack lead, speaker & power clip to the board.