1. REAL TIME ALARMS RECEIVED FROM A REAL TIME ALERT: When the door/window is opened or closed, the sensor immediately sends an instant notification to your smartphone. 2. Press warning message: When the door/window is triggered, you will receive an alarm signal on your phone. Convenient for monitoring doors, windows, cabinets, drawers, or any area where you want to be notified upon opening or closing. 3. Only works with 2.4 GHz WiFi connection: It connects to your smartphone via an app under a 2.4G WiFi environment. If your WiFi router only supports 5G, the device will not connect. 4. Compatible with Alexa and Google Home: It can also perform automated control alongside other smart devices compatible with Smart Life. The sensor requires two AA batteries (not included). When the battery level is low, the app automatically sends a reminder to the batteries, so you don't have to worry about them running out.