Kestrel 3000 Pocket Weather Station tracks maximum and average wind speeds along with current readings. Displays wind speed knots, meters per second, kilometers per hour, miles per hour, feet per minute or Beaufort force. Temperature, wind chill, heat index and dew point temperature can be displayed in °C or °F. Relative humidity is expressed as a percentage. Measuring modes and display units can be changed at any time and all functions are controlled with two buttons. A hard, slip-on case protects the display, buttons and impeller. Two-year manufacturer's warranty. Minimum wind speed: 0.7 mph (0.6 knots, 1 km/h, 0.3 m/s, or 60 fpm). Maximum wind speed: 89 mph (78 knots, 144 km/h, 40 m/s, or 7,830 fpm). Wind speed accuracy: ±3%. Update: 1 second. Temperature and wind chill accuracy: ±1°C. Wind chill factor resolution: ±1°C. Relative humidity accuracy: ±3% from 5% to 95%. Dew point temperature accuracy: ±2°C. Heat index accuracy: ±3°C. Humidity sensor can be recalibrated in the field. Temperature resolution: ±0.1°F (±0.1°C). Operating temperature: -4°F to +140°F (-20°C to +60°C). Temperature range: -20°F to +158°F (-29°C to +70°C). Impeller: 1" diameter, sapphire bearings, light weight. Temperature sensor: hermetically sealed precision thermistor. Humidity sensor: silicon based capacitive sensor. Display: reflective 3-1?2 digit LCD. Sealing: electronics enclosure IP67 – water resistant to 3 ft. Floats. Battery: user-replaceable CR2032 coin cell battery with a typical life of 400 hours. Dimensions: 4.8" x 1.7" x 0.6".