View Cart “Shure BLX Cardoid Condenser Wireless Headset System: Includes the BLX4 receiver with microprocessor-controlled internal antenna diversity, the BLX1 bodypack transmitter, delivering up to 14 hours of continuous use with 2 AA batteries. and a 300 ft (100 m) transmission radius, & a PGA31 cardiod condenser headset mic. SH-BLX14P31-1” has been added to your cart.