A professional digital anemometer with stable performance, safety and reliability. Features: [Wide Application] It can measure air velocity and air volume, which can be used in wind energy, meteorology, industry, agriculture, hydrology and water conservancy, environmental protection, highways, airports, etc. [Various Units of Measure] Press the UNIT button to select unit(m/s, km/h, mil/h, ft/m, ft/s, knots) when measuring air velocity; and select unit(CMS, CMM, CFM) when measuring airflow. [Accurate Measurement] Measuring range from 0.40m/s to 30.00m/s; supports beaufort scale from wind force 0 to 12. [Practical Function] Press the Data Hold button to freeze the displayed reading; auto power off in 10 minutes without any operation; maximum/minimum/average value mode is enabled. [User Friendly] Measures 7.75*2.67*1.1in and weighs only 4.79oz, featuring compact and lightweight; and LCD backlight ensures clear visibility even in low-light area. Note: *Batteries are not included. *Do not touch the fan blade with force. *Do not store or operate the instrument in area with high temperature or humidity. *In use, do not let the strong light directly shine on the fan, in order to avoid measurement errors. *Avoid violent vibration. *Remove the battery before storing the instrument for a long time. *To measure the airflow, the cross-sectional area of the tested air duct must be determined and input into the anemometer. Parameters: Display: LCD Max. Counts: 9999 Air Velocity: 0.40-30.00 m/s Sampling Rate: Approx. One reading per second Sensor: Air velocity/flow sensor; angled vane arms with bearing Beaufort Wind Scale: 0-12 Max/Min/Avg: Record and view minimum, maximum, average Data Hold: Freeze reading Operating Conditions: 0-40℃(Temperature), ＜80%RH(Humidity), ＜2(altitude) Auto Power Off: 10 minutes Power Supply: 3 * 1.5V AAA(LR03) batteries(not included) Accuracy Specifications: Air Velocity Measurements Range Resolution Accuracy m/s (meters per second) 0.40-30.00 0.01 ±(2.0%+ 0.5m/s) km/h (kilometers per hour) 1.40-108.0 0.01-0.1 ±(2.0%+ 1.8km/h) ft/s (feet per second) 1.30-98.50 0.01 ±(2.0%+ 1.6ft/s) ft/m (feet per minute) 78.00-5900 0.01-1 ±(2.0%+ 10ft/m) knots (nautical miles per hour) 0.80-58.30 0.01 ±(2.0%+ 1.0knots) mile/h (miles per hour) 0.90-67.10 0.01 ±(2.0%+ 1.1mile/h) Air Flow Measurements Range Resolution Area CFM (cubic feet per minute) 0-9999 0.01 to 1 0-9.999 CMM (cubic meter per minute) 0-9999 0.01 to 1 0-9.999 CMS (cubic meters per second) 0-9999 0.01 to 1 0-9.999 *The accuracy applies within one year after the calibration. *Reference condition: the environment temperature 18℃ to 28℃, the relative humidity is no more than 80. Specifications: Brand: SMART SENSOR Model: ST6816 Color: Red Material: ABS Item Size: 19.7*6.8*2.8cm / 7.75*2.67*1.1in Package Size: 24.3*9*5cm / 9.56*3.54*1.96in Item Weight: 136g / 4.79oz Packag