Brush Faceplates are commonly used to hide Audio Visual cables behind walls and so giving a clean appearance to your home rather than bundles of wires hanging down the wall or trailing around in the living room. Two plates are usually installed, one for entrance and the other for the exit of cables. Commonly these are at the top and bottom of the wall where the equipment resides.
When fitted directly onto a wall without a back box it will sit cleanly flush with the surface as the brush frame is designed not to protrude past the back of the Faceplate. This is important if you are fixing direct on to a surface with no backbox.
NOTE; They are not intended for use alongside other wall sockets in the same channel where hazardous voltages may be accessible through the Brush Plate.