The Kestrel 1000 measures instantaneous maximum and average wind speeds. Measurement unit options are knots, meters per second, kilometers per hour, miles per hour, feet per minute and Beaufort. Hold it up to measure wind speed. Large, easy-to-read liquid crystal display with +/-3% accuracy. Measures down to 0.3 m/s (0.67 mph). Impeller and protective housing pop out for easy and inexpensive replacement. Includes slip-on hard case that protects the impeller, buttons and display from damage in your pocket or toolbox. It is waterproof and it floats. The replaceable battery provides 400 hours of use. 5-year warranty.