The Kidde P3010CU is a 10-year, sealed battery, smoke and carbon monoxide alarm with a voice warning system 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's overall performance and significantly reduces the potential for a nuisance alarm.