10 Year Smoke Carbon Monoxide Alarm, Detects Both Carbon Monoxide Smoke In A Single Device, It Is Designed For Hardwired Installation But Features A 10 Year Battery Back Up That Allows The Unit To Function In The Event Of A Power Outage, Carbon Monoxide Smoke Detector Can Be Connected To Other Compatible BRK Or First Alert Carbon Monoxide Smoke Detectors Within A Single Family Residence, Single Button Silences Or Tests The Unit, Hard Wired With Battery Back Up, ElectrochemicalIonization Sensor Type, NOTE Please Check Your Local Building Code Requirements Before Installing This Product To Determine Compliance With Applicable Standards