First Alert provides you the best affordable fire protection equipment in Canada. This Battery powered combination smoke and carbon monoxide alarm contains both photoelectric and electrochemical sensors. The interconnectivity alarm features interconnectivity, a Mute/Silence button to quiet false alarms and an easy access battery drawer allowing batteries to be changed without removing the alarm from the ceiling. 5-year limited warranty. For more info visit us: https://firstalert.ca/product/sco500nva-onelink-battery-operated-combo-carbon-monoxide-and-smoke-alarm/ .