how to use: 1. Scan the QR code on the package and download the APP 2. Open the APP and make sure the Bluetooth of the APP is on. 3. Remove the battery cover, the sensor starts working. 4. Click "Add device" or "+" to add a hygrometer. Spare battery: 1. Wash your hands and make sure there is no water or oil. 2. Hold the device and pull it towards the ground. 3. Remove the battery and replace it with a new CR2477 battery. 4. & n Size 35x15 (mm) Weight 50 grams [Small and portable] The temperature and humidity meter is small in size, easy to carry. carry, does not take up much storage space, and has a superior carrying design that can be hung on a hook on the wall. [Real-time monitoring] After connecting to the APP, upload the data to the APP and generate a curve in the APP, so that you can intuitively understand the temperature and humidity changes, record and analyze, and take care of your family's health. Data storage functionBuilt-in storage function, record temperature and humidity every 10 minutes, data can be exported as CSV files and can be shared with friends. [High Accuracy] A MEMS digital temperature and humidity sensor is used, the measurement is stable and accurate, and the refresh rate is e st of 1 second/times. Wide ApplicationWidely used in greenhouse planting, farming, greenhouse, cold chain, warehouse, indoor, pharmacy, etc. Features: 1. Small and PortableThe temperature and humidity meter is small in size, easy to carry, does not take up much storage space, and has a superior carrying design that can be hung on a hook on the wall. 2. [Real-time monitoring] After connecting to the APP, upload the data to the APP, and generate a curve in the APP, so that you can intuitively understand the temperature and humidity changes, record and analyze, and take care of your family's health at all times. 3. [Data storage function] Built-in storage function, temperature and humidity recording every 10 minutes, data can be exported as CSV files and can be shared with friends. 4. [High Accuracy] A digital MEMS temperature and humidity sensor is used, the measurement is stable and accurate, and the refresh rate is 1 second/time. 5. [Wide Application] Widely used in greenhouse planting, breeding, greenhouse, cold chain, warehouse, indoor, pharmacy, etc.