The Kidde® P3010K-CO is a 10 years, sealed battery, smoke and carbon monoxide alarm that features photoelectric and electrochemical sensing technology with smart hush feature. This combination alarm combines the detection capabilities of a photoelectric sensor with that of an electrochemical sensor, which is used to detect CO. When either sensor notices a potential hazard, it will communicate with the other. Depending on what is detected, the alarm will adjust its smoke sensitivity in order to better discriminate between a real hazard and a false one. This constant communication enhances the alarm overall performance and significantly reduces the potential for a nuisance alarm. Kidde® Carbon Monoxide Smoke Alarm, Worry-Free Kitchen, Sealed Lithium Battery Power Source, Electrochemical/Photoelectric Sensor, Alarm: Audio, 85 dB Alert, Red LED Visual Alert, 10 to 85 % Humidity, Audible Alarm/LED Display, 40 to 100 deg F Operating, Plastic, White, 5.22 in Dia x 1.6 in D Dimensions