Experience the next level of fire safety with the Kidde Hardwired Smoke Detector, AA Battery Backup, Interconnectable, LED Warning Light Indicators, 4 Pack, model 20SAR. This smoke detector has enhanced sensing technology that reduces false alarms often caused by cooking and sends fast alerts that help give your family more time to get out safely. Plus, it is interconnected so when one alarm sounds, they all do so you never miss an emergency (see user guide for compatibility with other Kidde models). This alarm offers a modern 5-inch design ideal for all living spaces such as living rooms, hallways, kitchens, & bedrooms. Comprehensively tested and designed to the latest UL standard for safety and reliability, the 5-inch smoke alarm is powered by 120V AC wiring with 2 AA alkaline replaceable backup batteries (included) for continual detection even during outages. Batteries should be replaced every 6 months. In addition, the detector is self-testing and easy to install with the included twist-and-click mounting bracket. Meets requirements of 9th Edition UL 217, FCC, and CSFM.