Smart Door Alarm Sensor, Window and Door Sensor Wireless Home Alarm System for Home Security Free APP Mode For Tuyasmart, WiFi or AP one click to connect the wifi. Long transmission distance Up to 45 meters and strong network signal. Compatible with Alexa and Google home Can work independently without a hub and is compatible with Alexa and Google home. Ultra-long standby timeUltra-long standby time. 2 AAA batteries for power supply (not included), whose standby time lasts 5 years. WiFi Smart Door AlarmBy connecting WIFI (2.4G only) and mobile phone connection, the alert will be sent to mobile phone via app when abnormal condition is detected. Note: The data is all manual measurement, please allow 1 - 3cm error, due to the Light and display difference, there will be a certain color difference, depending on the physical object received Delivery Quantity: (according to the main image)