First Alert, 10 Year, Hardwired Smoke & Carbon Monoxide Detector, Ionization Smoke Sensing Chamber & An Electrochemical Carbon Monoxide Sensor, 10 Year Battery Back Up Allows For Continued Monitoring, For The Life Of The Alarm. Intelligent Sensing Technology Is Designed To Reduce Nuisance Alarms, 1 Button Silences Them If They Do Occur, Tests Detector Functions, Latching Alarm Indicator Automatically Identifies Which Unit Initiated The Alarm, Even After The Conditions That Set Off The Alarm Have Subsided, End Of Life Signal Enhances Your Safety By Letting You Know When It's Time To Replace The Unit, 2 Locking Features Prevent Battery Tampering, & Installation & Connection To AC Power Is Easy With The Quick Connect Wiring Harness, Connect It To Compatible BRK Or First Alert Alarms Within A Single Family Residence, Connecting Will Sound All The Alarms Together.