The Kestrel 3500 Pocket Weather Meter comes packed with function. With a single hand-held device you can monitor barometric pressure (trends up to 3 hours); altitude; relative humidity; heat stress index; dewpoint; wet bulb temperature; wind chill; air, water, and snow temperature; and current, average, and maximum wind speed. Engineered for performance, the 3500 is individually calibrated and features a backlit screen, patented impeller and sensor technology, quick-response external temperature sensor, and temperature-controlled humidity sensor. The rugged design features a protective cover with sure-grip overmolding, is fully waterproof and floats (IP-67), and is drop-tested to MIL-STD-810F standards. The 3500 is also made for easy maintenance - no tools are required and the impeller is user-replaceable. With the accurate environmental information it provides, first responders and emergency medical personnel can measure and track conditions relating to heat stress and exposure, and issue guidelines and warnings for field personnel. Within seconds of arriving at a scene, police, SWAT, special operations and first response personnel can gather the weather data they need quickly and accurately. Effective and safe K9 operations also require close monitoring of the wind speed, temperature and humidity conditions in the area where the dogs are working. Weather enthusiasts, researchers and academics will appreciate the 3500's accuracy and reliability whether in a classroom, laboratory or in the field. From environmental conservation, marine and ocean research to cave research and scientific expeditions, the Kestrel 3500 makes gathering real-time data simple. Coin cell battery and lanyard included. The Kestrel 3500 is proudly designed and manufactured in the USA, and is backed by a 5-year warranty.