ADT Inc.

ADT installs security systems in homes and small businesses that detect break-ins, fires, carbon monoxide, and other emergencies. When an alarm goes off, ADT's monitoring centers receive the alert and can contact emergency services or the customer. The company also offers smart home automation that lets customers lock doors, control lights, and watch security cameras from their phones. ADT sells both professionally installed systems and do-it-yourself kits, and provides ongoing maintenance and monitoring services.