TVOC, Temperature and Humidity Sensor: An Aqara Hub is required and sold separately. Requires a secured 2.4 gigahertz Wi-Fi network connection. The Aqara TVOC Air Quality Monitor detects the concentration of the Volatile Organic Compounds (VOCs) which are harmful, carcinogenic air pollutants that evaporate at normal indoor atmospheric conditions, and measures temperature and humidity, which can also be used in smart home automations..UNAUTHORIZED ENTRY DETECTION: Whenever unexpected motion is detected, the Aqara Motion Sensor will send an alert to your phone and activate the local alarm sound on Aqara Hub..All-Round Compatibility: Zigbee 3.0 Protocol built upon the fastest and energy-efficient smart home technology with the focus on compatibility and stability. Apart from Aqara Home, it supports the most popular smart home ecosystems such as HomeKit, Google Home, Alexa, IFTTT and more..HOME AUTOMATION: The Aqara Motion Sensor can be set to trigger the Aqara Hub alarm or other connected devices such as the Aqara smart plug when movements are detected..Portable & Lightweight: The Aqara air quality meter is compact and very easy to carry, size: 1.6*2.9*0.55 inch. Stylish exterior and durable materials ensure the long time using. This air quality tester is ideal for living room, bedrooms, cars, offices, school, and other indoor occasions. Especially the places with babies, kids, the elderly and pregnant women.