About this itemProtect Your Family with Advanced Smoke Detectors Photoelectric smoke sensor fewer false alarms, responds in 1 second,and is 5 times more accurate than traditional sensors,helping reduce false alarms and faults. Hightly sensitive real-time detection,secure your home with Jemay.Install in Only Minutes Smoke alarms can be mounted quickly and cleanly with this magnetic assembly system.Magnets and screws are included,you can choose any installation method you need.Smoke Detector Battery (Include) with 9v Replaceable Battery for smoke alarms. Reliable Battery Replacment Reminders Function. Thanks to an advanced built-in chipset, this battery smoke detector constantly monitors itself and quickly warns you of faults of faults and/or a low battery.Receive uninterrupted 24/7 protection .Low Battery-Non Disturb Fire detector with test-silence button. When low battery warning, press the test button, it can effectively mute for 10 hours. Fault warning , when the battery smoke detector is malfuntioning, a chirp will occur between flashes of the red LED.