Keep your home safe from fire! The First Alert(R) Photoelectric Smoke Alarm features a new, slim-round design and uses maximum-protection photoelectric technology. It lasts a full 10 years without needing to have a battery changed, and patented smoke entry system allows for a direct path to the smoke sensor, minimizing the nuisance of alarms that come from cooking smoke or shower steam. In addition, this maximum protection smoke and fire alarm uses photoelectric smoke sensing technology that detects smoke particles most commonly produced by smoldering fires and a highly accurate electrochemical sensor to detect carbon monoxide gas. A loud, 85dB alarm sounds if hazard is detected and a single test/silence button mutes unnecessary alarms and tests function. Simple twist/lock mounting bracket makes it quick and easy to install and an end-of-life timer sounds when it's time to replace your alarm. Backed by a 10-year limited warranty from First Alert and powered by sealed, 10-year lithium batteries, this alarm will provide continuous protection for your family and home for years to come!