NOTE: This product requires the HOBOmobile App to operate Convenient wireless setup and download via Bluetooth Low Energy Retrieve data in hard-to-reach locations Visual alarms alert you to out-of-range conditions Compact, weatherproof housing with built-in mounting The Onest MX2301 HOBO Weatherproof Temperature and Relative Humidity (RH) Data Logger has built-in temperature and relative humidity sensors. Leveraging Bluetooth Low Energy, the logger enables easy, fast set up and data download directly from your mobile device, and provides high accuracy measurements in harsh outdoor environments.