Protect your family with the Kidde Code One Carbon Monoxide Detector, Battery Powered, CO Detector. The Kidde Code One Carbon Monoxide Detector, Battery Powered, CO Detector operates on 3-AA alkaline batteries in a battery compartment in the back of the alarm. Using electrochemical sensor technology, the Code One Carbon Monoxide Detector alerts to poisonous carbon monoxide gases, even during power outages. A green LED light will blink to indicate that smoke alarm is in operation, while red LEDs blink to indicate carbon monoxide has been detected. After 10 years of use, the Kidde Code One Carbon Monoxide Detector, Battery Powered, CO Detector will need to be replaced. UL Certified with a 10-year limited warranty. Meets requirements of UL2034.