Chamberlain Wireless Doorbell & Intercom

First of all, I don't usually write product reviews but this system solved a major problem for me. My 4 story, 8000 sq. ft. home is built from an Insulated Concrete Form system (IFC) and has 10 inch concrete and steel reinforced walls. I have large dogs and needed a doorbell/intercom outside the fenced yard as well as a way to monitor dogs scratching at the door. I mounted the doorbell about 40 feet from the house and placed one intercom right inside the back door. Not only can I hear the doorbell, I can also hear what's going on at the back door or in another room (using the monitor feature). I have purchased other systems in the past but they just could not penetrate the thick concrete walls. This one is fantastic right out of the box. I added an additional set of intercoms (Chamberlain NLS2) and found the set up and installation to be very simple. Overall a great system at a very reasonable price.