Brand new kidde smoke alarm. Never used and ready to be installed. Buy at half price here! Kidde 21026063 AC Hardwired Smoke Detector Alarm with 9V Back up and Front Load Battery Door, White BrandKidde StyleClassic Power SourceHardwired ColorWhite Product Dimensions4"D x 4"W x 2"H Item Weight8 ounces Ionization sensor technology senses invisible fire particles, associated with fast flaming fires Smoke alarm operates on a 120V wired power source with a 9-Volt alkaline battery backup (included) Front-loading battery door allows for easy change of the battery without removing the alarm from the mounting bracket Test-Hush button makes it easy to test the smoke detector and silence false alarms that occur from cooking or shower steam