The Kidde KN-COB-IC is an AC wire-in carbon monoxide alarm that warns you and your family of dangerous carbon monoxide levels. It includes multiple contractor friendly features to ensure easy installation and minimal troubleshooting. This alarm interconnects with up to 24 Kidde devices (of which 18 can be initiation) including smoke alarms, CO alarms and heat alarms on one wiring network. Includes a 9V battery backup along with a 5-year limited warranty.