Come and see our amazing products. There is a small fan in the head, when wind blows, it can test the speed and rotate. Easy to Read: Large LCD Display with Back-light. Professional measuring instrument with large screen LCD display and back-light, easy to read data in dark environment. Professional to measure air velocity and air temperature accurately. This meter displays wind speed in 5 parameters (m/s- km/h- ft/min- knots & mph) and temperature is switchable between C and F. It also provides Current- Maximum- and Average speed measurement and Wind Chill indication. This anemometer is a professional tool for windsurfing, sailing and kite flying. You can also use it for industrial and home purposes such as measuring speed and temperature of CPU computer fans, air-conditioners, airflow over the roof or walls. Pls confirm with us about the packing info, stock color and exact production time before placing your order.