Kidde 2101016 Worry-Free Sealed Lithium Living Area Smoke Alarm (Dc)

This Kidde Worry-Free Hallway Smoke Alarm is equipped with a ten-year sealed lithium battery, photoelectric sensing technology, and a Smart Hush feature. When smoke or fire is detected, the 85 dB alarm provides a safe escape. Alarm is fully automatic and activates when attached to mounting bracket. There are never any batteries to buy or replace. And at the end of its alarm life it chirps, letting users know it needs replacing.