The ultra-compact door station is only 3.25" (83mm) wide and has a built-in voice amplifier. It easily mounts right on the surface of the wall and has a built-in rain hood. There are no visible mounting screws from the front, and built-in L.E.D.(s) illuminate the push buttons. All that is required to power the system (and door opener) is a plug-in transformer (included in each kit).