Smoke Detector, Hardwired Interconnected Smoke Detectors, Smoke Alarm with Replaceable 9V Battery, Interconnects Up to 12 Fire Alarms Smoke Detectors, Photoelectric Fire Alarm with Test/Silence Button

[Hardwired interconnection] Up to 12 smoke alarms may also be interconnected to cover your whole home. When one detects smoke, they all make a sound to alert everyone in the house, creating an interconnected safety net for your home.
[9V Battery backup] Hardwired smoke detectors are equipped with DC 9V batteries. Be sure that all units are at all times connected and continue to function properly, even in the event of a power failure. Low battery alarm reminds you to replace the battery as soon as conceivable. If an error occurs, the system automatically triggers the fault mode, prompting you to check the device.
[Test Mute button and LED light] It is attached with other alarms. Just press the test/mute button on some of the units to test or mute all the interconnected system. If the smoke alarm is in normal working condition, the green LED light is at all times on and the red LED light flashes each and every 32 seconds
[Photoelectric smoke sensor] Based on advanced photoelectric technology, smoke alarms may also be more sensitive, fast, accurate measurement of smoke levels. More than 85 decibels of alarm sound, you’ll be able to more clearly hear the danger coming.
[Simple installation] The installation of smoke alarm is very simple. The AC connector is attached only to the mains power and signal cables. (Please connect as instructed)