Smoke Detector Fire Alarm, 2 Packs Photoelectric Smoke Detectors with UL Listed, 9V Battery Operated Smoke Detector (9V Battery Included), 10 Years Life Time, Fire Safety for Home, Hotel, School etc

【High Sensitive & Quick Responsive】: This smoke alarm adopts photoelectric technology to detect smoke. More sensitive to light smoke and slow smoldering fires, Timely alarm. Even in sleeping, there is no need to worry.
【Alarm Condition】: When the smoke alarm device detect particles of combustion and the concentration of smoke reaches the alarm threshold, the red LED will flash rapidly (one flash per second).The rapid flashing LED and pulsating alarm will continue until the air is cleared or the test button is released.
【Easy Installation】: Comes with a mounting bracket, screws and anchor plugs, just drilling holes in appropriate positions. Powered by one 9V battery (included), it will not be affected by power outage. Low power consumption, service live about 10 years. When an intermittent “chirp” accompanied by a red LED flash every 32 seconds indicates a low battery.