Sony's WCS-999 Wireless Microphone System is for use with video camcorders and portable audio recorders. The system features a transmission range up to 150 feet, depending on conditions, and a 900 MHz FM transmission for high-quality sound. The Complete Kit includes: a Lavalier Mic, Transmitter, Receiver and Monitoring Earphone, Three Channels with a Selector Switch for low interference, and a Compact, Lightweight Design