BOYA BY-MP4 is a 2-channel audio adapter, with a 3.5 mm TRRS cable and a 3.5 mm TRS cable that allows you to record videos with a smartphone, DSLR camera, or camcorder. This adapter provides a compact dual microphone mounting and audio mixing solution. It allows you to easily mount and control two microphones or wireless receivers. It requires no batteries or power source. It features three built-in mounting shoes to attach a variety of microphones or wireless receivers, as well as other accessories.