Kestrel takes weather monitoring to a whole new level with the Kestrel 4000 Pocket Weather Tracker. Kestrel has packed this hand-held weather tracker with the technology to monitor barometric pressure, altitude, density altitude, temperature, humidity, wind speed, wind chill, dew point, wet bulb, and heat index. No other hand-held comes close to the power and accuracy of the Kestrel 4000. If you are serious about the weather or need to be on top of the environmental conditions around you, this unit will never leave your side. You simply cannot find a weather tracker that measures every major environmental condition as easily and accurately as the Kestrel 4000.