DUAL TONE BELL MUSICAL TONE ANNOUNCES THE ARRIVAL OF VISITORS This wireless system is very easy to install whitout ruining the decore of your home or office. This wireless unit consumes very little power and alkaline batteries may last as long as one year.Special circurity provides a high quality tone signal. As a result of our high power circuitry, this unit can be placed almost anywhere while providing a powerful tone signal This is suitable for homes, office buldings, factories, hotels and where ever a remote control door chime is needed.