First Alert 1039871 Smoke and Carbon Monoxide Alarm, 85 dB, Alarm: Audible, Electrochemical, Photoelectric Sensor

The first Alert PRC710V combination photoelectric smoke and carbon monoxide alarm with ten year battery and voice and location helps protect your home from two potentially deadly threats by providing up to a decade of uninterrupted monitoring. Equipped with dual sensors, this low profile alarm detects smoke from slow-burning, smoldering fires. Half as thick as a standard alarm, this detector has a slim, contemporary design that mounts unobtrusively on a wall or ceiling. A built-in 10 year lithium-ion battery provides continuous power, with no need to ever worry about changing the battery during the lifetime of the alarm.