Shure BLX2/SM58 Handheld Wireless Microphone Transmitter with SM58, J10 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 and -10 dB gain attenuation 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