The units will automatically detect each other and choose the best channel from all 6 channels

Buy at www.musicianscart.com NUX B-3RC Microphone Wireless System with Charging Case Microphone Bundle 2.4GHz 24-bit/44.1kHz Audio Quality,B-3RC has auto pairing and channel group selection, Plug the Transmitter (TX) to your mic Receiver (RX) to PA system and you are good to go, The units will automatically detect each other and choose the best channel from all 6 channels,Easy to use 2.4GHz wireless microphone system,24bit Hi-Resolution audio quality,Ultra-low latency<4.8ms,Auto pairing and auto channel selection,Long-lasting built-in lithium battery(3.5 hours working time),2.4GHz operating frequency,24 bit sampling accuracy,Latency <4.8ms,Transmission Range Up to 100 feet line-of- sight,THD + Noise <0.1% @ 1kHz,Built-in Battery Capacity (TX& RX) 330mAh/3.7V,TX/RX Battery Running Time 3.5 hourse,TX/RX Battery Charging Time around 2.5 hours,Storage Box Battery Capacity 3000mAh/3.7V,Storage Box Battery Charging Time around 4 hours