This is the Audio-Technica ATW-RU13 receiver unit designed for the System 10 Pro.
The System 10 Pro wireless family features a 24-bit operation. You can connect this via ethernet cable to mount it over 300' away from the receiver and still get strong signal strength. Up to five chassis (10 receiver units) can be linked using the RJ12 cable included with each system, creating a stable, multichannel system with the simultaneous use of up to 10 channels. When you go with the Audio-Technica System 10 Pro series, you are ensuring yourself quality and reliability.