First Alert 0827B 10-Year Tamper Resistant Smoke Alarm, White Help keep your family safe with this battery-operated smoke alarm; the 10-year lithium-ion battery offers continuous power for the life of the alarm and provides continued monitoring even if there's a power failure Alarm features an ionization sensor for smoke detection, which is effective in recognizing smoke from flaming fires such as paper and grease fires Battery-operated unit provides continuous monitoring even if there's a power failure: plus, it's easy to install Alarm also features loud 85-decibel alarm, easy mounting bracket, a single test/silence button, and an end-of-life signal so you know when to replace the unit To ensure complete protection make sure to place one on each level of your home and in each bedroom Complies with all current 10-year legislation in states/cities where required No Battery Changes for the Life of the Alarm; 3V Lithium Power Cell Included Ionization Sensor Perfect Mount allows for easy alignment of alarm 10-Year Limited Warranty