Features: The smart windows door sensor can detect the opening and closing of door and windows and send a notification to your phone via the APP. With the ability of matching with other Xiaomi smart devices such as gateway remote control, smart bulb, air cleaner, etc. this sensor is able to help you create a smart home. The windows door sensor consists of a sensor subject and a magnet. It detect the opening and closing of door and windows by sensing the near and separation of the sensor subject and magnet. Smart door and windows sensor for daily security.ZigBee wireless connection. Trigger and alarm: it will light and ring when someone open the door, the light will automatically turn on when someone push the door. Away from home mode: If someone broke into, the bell will ring and the IP camera (not included) will take video. Intelligent sensors: open the window let fresh air into room. Small size, easy to install. Built-in 1pc CR1632 cell battery. Please download APP "Mi Home". Specifications: Condition: Brand New Material: ABS Color: White Max. sensing distance: 22mm Working temperature: -10 - 50℃ Working humidity: 0 - 95pct RH Package List: 1 * Door Magnet (Battery Included) 1 * Manual Please Note: This item must match the xiaomi multifunctional gateway to use. 1、The smart windows door sensor can detect the opening and closing of door and windows and send a notification to your phone via the APP. 2、With the ability of matching with other Xiaomi smart devices such as gateway remote control, smart bulb, air cleaner, etc. this sensor is able to help you create a smart home. 3、The windows door sensor consists of a sensor subject and a magnet. 4、Intelligent sensors: open the window let fresh air into room. 5、Away from home mode: If someone broke into, the bell will ring and the IP camera (not included) will take video.