Audio-Technica ATW-R3100b 3000 Series Wireless Receiver Channel D Antenna power available for powered antennas & other in-line RF devices Nine pre-coordinated frequency scan groups simplify selection of usable frequencies in a multichannel wireless system True Diversity operation reduces dropouts Advanced digital Tone Lock squelch effectively blocks stray RF and communicates transmitter data for receiver display The receiver is half-width for a standard 1U 19" rack mount; rack-mount adapters are included