The First Alert SMCO210 10-Year Sealed Battery Combination Smoke Carbon Monoxide Alarm with Slim Profile Design uses First Alert's Precision Detection advanced sensing technology and meets new industry standards. This 2-in-1 alarm provides convenient protection against both fire and carbon monoxide (CO). Also equipped with a 10-year sealed battery to eliminate the need for battery replacements and low battery chirps. First Alerts Precision Detection advanced sensing technology complies with new industry standards to reduce cooking nuisance alarms and provides early warning in the event of a home fire emergency. Provides reliable 2in1 protection against both smoke and carbon monoxide in an easy to install alarm 10Year sealed battery eliminates battery replacements and low battery chirps for the life of the alarm Endoflife warning lets you know when its time to replace the alarm Slim profile design is half the depth of a standard alarm