The NXT-5R Wall Switch Reader measures 4.18 inches high by 2.95 inches wide by 0.625 inches deep (10.6 cm high x 7.5 cm wide x 1.6 cm deep) and can be mounted on a US single gang electrical box or flat on a wall. Read range is up to 6” (15 cm) when mounted at least 1” off metal. If the reader is mounted using a metal electrical junction box with the thickness of the wall material separating the reader from the box, read range will be slightly reduced.