Receive real-time alarms remotely: When the door/window is opened or closed, the sensor will send an instant notification to your smartphone immediatelyPush Alert Message: When the door/window is triggered, you will receive an alarm signal from your phone.Convenient to detect your doors, windows, cabinets, drawers, or anywhere you want to notify when opened or closedOnly works with 2.4GHz WiFi Connection: It connects to your smartphone via APP under 2.4G WiFi environment. If your WiFi router only supports 5G, the device will not connectCompatible with Alexa and Google Home: It can also perform automatic control with other smart devices compatible with Smart Life.The sensor door requires two AA batteries (not included).When the battery level is low, it will automatically push messages through the app to remind you to change the battery, don't worry about running out of batteryEasy installation: no need to use complicated tools when installing, just use 3M glue to install, firm and durable.The distance between the two components should be as close as possible, and the closer distance should not affect the opening/closing of the door or window