It's a security alarm system that you probably already have and requires no installation. Test it. It will go off from most everywhere inside your house and will keep honking until your battery runs down or until you reset it with the button on the key fob chain. It works if you park in your driveway or garage If your car alarm goes off when someone is trying to break in your house, odds are the burglar rapist won't stick around... after a few seconds all the neighbors will be looki ng out their windows to see who is out there and sure enough the criminal won't want that.