External Sensor for Temperature and Humidity Measurements in an Outdoor Environment Wireless Transmission of Recorded Readings to Smartphones or Tablets Using Bluetooth Smart LE Communications 0 to 100% RH and -40°C to 70°C Measurement Ranges with a 2.5% RH and ±0.2°C Accuracy User-Replaceable Lithium Battery with 2 Year Typical Life (1 Minute Sampling Rate) Includes Temp/RH Sensor, Screws and Zip Ties for Mounting. HOBOmobile App Available on the Apple Store The HOBO MX2302A is a weatherproof data logger with external 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.