The AO-BT04B is a low-power Bluetooth temperature and humidity data logger with the latest Bluetooth 4.0 technology and the Nordic N51822 chipset. You can collect the temperature and humidity of the environment and transfer it to smart mobile devices through Bluetooth 4.0. This data can be recorded as historical data. The BT04B can store up to 12,000 pieces of temperature and humidity data. The mobile phone with Bluetooth 4.0 or higher can download and install the application configuration tool. You can store and control the temperature and humidity of the environment fully. Its characteristics are small, not too heavy, easy to carry and very accurate for a wide use in cold chain logistics, archives, laboratories, refrigerators, etc.