2 Pack, 9V, Battery Operated, Fire Alarm, Ideal For Detecting Fast Flaming Fires, Ionization Smoke Alarm Technology Detects Smoke As Soon It Enters The Chamber Sounds The Siren, Single Test Button Checks The Functionality Of The Device, Slide Out Battery Drawer Allows Easy Battery Placement Locks Into Place, , NOTE Please Check Your Local Building Code Requirements Before Installing This Product To Determine Compliance With Applicable Standards