This four-channel home intercom system allows you to talk to any room in your house without additional wiring or remodeling, and during product testing by the Hammacher Schlemmer Institute, this easy-to-install unit rated highest among tested models for ease of use and sound quality. The intercom modules transmitted clear, uninterrupted sound over 1,500' sq. Our analysts found the system much easier to set than other models with confusing instructions and frequency codes. You can switch among any of the four channels with a push of a button; your voice activates the system, and indicator lights show which channels are active. Includes two units; can be expanded with more intercoms sold separately below. Plugs into AC. May not work in rooms with dimmers or GFCI outlets. 5 3/4" H x 7" W x 1 3/4" D. (1 1/2 lbs.)