The R-300 is an infrared sensor that forms part of a hidden link system that allows control of sources from different locations. It is made for use in the special knockouts in our speakers or for mounting in a wall. This means that you can hide it totally behind the grille in a in-wall speaker. The R-300 can pick up signals from a remote from approximately 30 ft/9 meters depending on the strength of the remote's transmissions. Sold individually. By Jamo.