The portable anemometer provides fast, accurate readings, with digital readability and the convenience of a remote sensor separately. Multi-functions for air flow measurement m/s, km/h,. ft/min, knots. A sensitive balanced vane wheel rotates freely in response to air flow. Built-in low battery indicator. Data Hold function for stored the desired value on display. Large LCD display, easy to read. Measuring Range : 0.4 to 30.0m/s. Suitable to operate on 9V Battery