[Features] ● Can be directly placed inside refrigerators, self-powered with built-in batteries, quick installation without engineering work. ● Optional sensors for Temp, Temperature and Humidity, Carbon Dioxide," , "PM2.5"or "TVOC" measurements. ● Utilizes Bluetooth Mesh architecture instead of traditional star topology. ● The device itself serves as both a sensor and a communication relay. ● Built-in battery with a capacity of up to 15000mAh. ● When equipped with a temperature and humidity sensor, with good communication, the battery can last for over two years with one-minute interval sensing. ● Indoor point-to-point transmission distance of up to 20 meters, up to 50 meters outdoors. ● Communication signals can span across rooms and floors within indoor spaces and even across buildings. ● Up to 10 levels of relay hopping in communication transmission. ● Can simultaneously receive signals from 30 sets of temperature and humidity sensors. ● Able to read the response status of all sensors, providing insights into the communication status of the field. ● TAF certified. [Applications] Suitable for use in medical/vaccine refrigerators, greenhouses, indoor air quality monitoring.