The ECM-AW4 Bluetooth Wireless Microphone System from Sony is a complete battery-powered Bluetooth wireless microphone system. It plugs into virtually any kind of video camera, DSLR, or recording device that features a 3.5mm mini-jack microphone input. The transmitter has a built-in mic, or you can use a separately available external mic with 3.5mm output (Plugin Power supported). Receiver unit has a talk-back function that allows the camera operator to communicate clearly with the subject. The mic has a range of up to 150 feet.