Slim photoelectric smoke alarm with 10-year battery helps protect homes by providing up to a decade of uninterrupted monitoring. Uses an ultra-reliable photoelectric sensor to detect smoke from slow-burning, smoldering fires. Half as thick as a standard alarm, features 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 over the lifetime of the smoke detector.