About this item The high-quality photoelectric smoke sensor is more sensitive at detecting smoke from smoldering fires and sounds quickly to alert you of any fire hazard With the 10-year sealed battery smoke alarm, you won’t have to worry about changing the battery and your home and family are always protected, even during power outages The fire alarm’s coverage range is 215–430 ft² (20–40 m²), detecting fires from all sides; at over 85 dB, the 10-year battery smoke detector sounds loudly when triggered, even awakening sound sleepers The smoke detector has an automatic self-test function; it tests the battery and photoelectric sensor every 60 seconds to ensure fast and accurate alerts The test/silence button allows you to easily test your alarm, letting you know that you and your family are always protected; you can also silence false alarms caused by cooking fumes, dust, or insects with the simple push of a button