For this wireless system component to work, please make sure your transmitter and receiver match in frequency range (style);Pairs with BLX4, BLX4R or BLX88 receivers (not included).;Power and battery status LED. Adjustable gain control;Quick & easy frequency matching. 300 feet (91 m) operating range (line of sight);2 AA batteries (included) provide up to 14 hours of continuous use. Receiver and transmitter must be in the same frequency