A Kestrel DROP is the world s easiest-to-use rugged and waterproof environmental data logger. Available in three models - the Kestrel DROP D1 Temperature Logger the Kestrel DROP D2 Temperature and Humidity Logger and the Kestrel DROP D3 Temperature Humidity and Pressure Logger - all three models allow you to monitor and record the conditions of any environment and easily access and chart real-time and historical data on your phone tablet or other smart device. The Kestrel DROP D3 data logger can be placed wherever needed to log temperature humidity heat index dew point temperature station pressure density altitude and pressure trend with the data logs retrieved wirelessly and automatically to the Kestrel Connect app when within wireless range (up to 100 or more line of sight). Each DROP measures just 1 x 1.8 x 2.4 inches (24 x 46 mm x 60 mm) and weighs just 1.2 ounces (34 grams). DROP loggers meet military and international standards for water dust and shock resistance (IP-67 and MIL-STD-810G) and are conveniently equipped with a sturdy d-ring for hanging wherever needed.