The Rolls HRS84 is a digital FM tuner/receiver. Functioning as an FM Receiver ONLY, not a transmitter the HRS84 features professional line level XLR outputs with a dedicated headphone out on the front of the unit. It operates in Mono or Stereo and two HRS84 can be rack mounted in a single standard 1U rack space. You can also use the Rolls URT5 (Universal Rack Tray) or RMS270 Rack Module System.