First Alert, Dual Sensor Smoke & Fire Alarm, Offers Comprehensive Monitoring For Smoke By Using 2 Different Sensors, A Single Button Silences The Alarm & Tests The Unit, While A Loud 85 Decibel Siren Is Designed To Alert Even The Soundest Of Sleepers, Battery Powered Design Allows The Fire Detector To Be Installed Easily, Ionization/Photoelectric Sensor Type, NOTE: Please Check Your Local Building Code Requirements Before Installing This Product To Determine Compliance With Applicable Standards.