1. 5 air speed unit conversion: m/s, ft/m, mph, km/h, Knots; 2 air temperature unit conversion: ℃/℉. 2. 12 levels air speed indication - You don' need to make complicated conversion from value to wind scale. 3. With backlight for easy reading at darkness. 4. Overall air speed display at MIN/Max/AVG. 5. with small volume, easy and convenient to use. 6. Perfect tool for measuring air speed , office, car, air condition, exhaust fan, sailboat, navigation, etc. Specifications: Air Speed: Range: 0-45 m/s, 0-140 km/h, 0-8800 ft/min, 0-100 mph, 0-88 Knots Resolution: 0.1 m/s, 0.3 km/h, 19 ft/min, 0.2 mph, 0.2 Knots Threshold: 0./s, 1 km/h, 60 ft/min, 0.7 mph, 0.6 Knots. Air Temperature: Range: 0-45℃, 32°F-113℉ Resolution: 0.2℃, 0.36℉ Accuracy: ±2℃, ±3.6℉ Operating Temperature: -10°C-50℃ / 14-122℉ Operating Humidity: 40% RH - 85% RH Storage Temperature: -20-60℃ / -4-140℉ Input Current: 3mA Power Supply: 1 x 9V 6F22 Battery (NOT included) Type:Tachometer name:Digital Anemometer Wind Colour:As Shown Material:plastic Package Contents: 1 * windmill 1 * host(Battery is NOT included) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.