The BY-MP4 Audio Adapter for Smartphones, DSLR Cameras, and Camcorders from Boya is a 2-channel audio adapter with a 1/8" (3.5mm) TRRS to 1/8" (3.5mm) Cable and a 1/8" (3.5mm) to 1/8" (3.5mm) Cable that allows you to shoot videos using various devices with a 1/8" (3.5mm) output. It can be used as a compact dual-mic mounting solution and audio mixing solution to control two mics or wireless receivers simultaneously. The BY-MP4 requires no batteries or power source. It is built with three integrated mounting shoes to attach a variety of microphones or wireless receivers, and can mount other accessories such as LED lights. In addition, there are two control knobs to adjust signal volume and a built-in switch for mono or stereo operation.