ZIGBEE STANDARD COMPATIBLE DOOR SENSOR: Works with most of Zigbee hubs or Echo devices with build-in Zigbee hub. SUIT FOR MOST DOORS AND WINDOWS AND 2-YEARS LONG BATTERY LIFE: The special design makes it possible to be installed in more places. Door Sensor uses two AAA 1.5V Alkaline batteries for power that can last for up to 2 years and it is very easy to replace them. UPGRADED THIRD REALITY APP AND SKILL FUNCTIONS: Connected with Third Reality Hub/Speaker, you can check the battery level in the APP, then replace the batteries in time; history record is also open to the users, so you can know when the state of the movement has been detected and deal with it in time. Enabled Third Reality Skill in the Alexa APP, you will have a low battery warning by emails.