The First Alert SMCO210 Sealed 10-Year Battery Combo Smoke and CO 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). The alarm is also equipped with a 10-year sealed battery to eliminate the need for battery replacements and low battery chirps. First Alert's 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.