The BLX14E/SM31 Headworn Wireless System is part of the BLX wireless systems family. Shure BLX Wireless Systems combine professional-quality sound with simple setup and an intuitive interface for legendary audio performance right out of the box. Precision-built and available in a variety of configurations, it’s the most accessible way to own the stage. Includes BLX4 wireless receiver, BLX1 bodypack transmitter, SM31 fitness headset microphone, power supply, clothing clip, windscreens, and user guide. Frequency: 518-542 MHz