Install the SM210 10-year sealed battery smoke alarm and CO400 battery-operated carbon monoxide alarm safety value pack for protection against fire and carbon monoxide (CO). The smoke alarm features First Alert's Precision Detection advanced sensing technology and meets new industry standards. While the CO400 carbon monoxide alarm easily installs and provides reliable CO protection. Features Precision Detection which provides advanced protection early warning and reduces cooking nuisance alerts. The smoke alarm includes a 10-year sealed battery meaning no battery replacement is required. The carbon monoxide alarm includes a 9-volt battery.