The Kidde Smoke Detector, 10-Year Battery, Photoelectric Sensor Smoke Alarm, model p3010b, uses photoelectric sensor technology to detect visible fire particles (associated with smoldering fires). When smoke or fire is detected, an 85-decibel alarm will sound. The Kidde Smoke Detector is powered by a 10-year lithium battery, for coverage during a power failure, while eliminating the need for battery changes. The Kidde smoke alarm automatically activates when it is attached to the mounting bracket. A test-hush button allows you to test the battery operations as well as silence nuisance alarms that may occur from cooking or shower steam. The Kidde Smoke Detector will chirp when it's time to replace the battery. Install a smoke detector & carbon monoxide detector on every level of your home and near bedrooms to help keep your family safe from fire & poisonous gas. UL Certified with a 10-year limited manufacturer's warranty. Meets requirements of UL 217, NFPA72 (chapter 11 2002 edition), NFPA101 (One and two-family dwellings), and Federal Housing Authority (FHA).