When placed adjacent to a compatible RF-consuming device, such as a Coal Generator or Powercell, it will scan for compatible devices and display them in the GUI. The device to monitor is selected by simply clicking on the item in the GUI. The player should then set the Mode to Less or More and adjust the slider to set the threshold percentage. In the illustration below, the lamp is lit because the Advanced Powercell contains less RF than specified in the GUI.
Note: The Redstone signal is only emitted from the rear face of the RF Monitor.