Pro Air CFM Anemometer: Accurately measures wind velocity in 5 units: m/s, km/h, ft/min, knots, mph. wind temp in / , air in CFM CMM. Allows you to record 600 groups of wind data, and comes with carrying storage case that provides good protection and keep everything together. Higher Range Wind Speed Meter: Higher Wind Speed Range: 0.001-100 mph (Accuracy: +/- 3% +/- 0.2 reading), Resolution: 0.001. Air temperature range 32.0-113.0 (0-45), Resolution 0.1. And also provides Current, Max, Min, 2/3 Max, Average of wind velocity, wind readings Airflow CFM Meter: BT-846A wind speed gauge measures Wind range: CFM 0-999900 ft3/min, Resolution: 0.001-100, Air area: 0.001-9999 ft2. You can just set the sectional area of the register or vent, the air volume display in CFM/ CMM synchronously during the air flowing measurement. Separated Extendable Wind Sensor: Built with user-friendly extendable wind sensor vane, so you can still look at the readings easily while you testing balancing the AC or dust collection system. 1.69 x 2.36 inch large Backlit LCD display can help you read the wind changes easily. Must Have for Air Balancing: Designed for HVAC trouble-, air balancing. The separated wind speed sensor can be replaced if it's broke to increase the service life. Manual or Auto power off after 5 mins without operation to save the battery. Features: Back Light Low Battery Indicator MAX/MIN for wind velocity Average/ 2/3MAX for wind Records 600 groups of measurement Data holding, storing and deleting function Manual / Auto Power Off after 5 min without operation Unit optional for wind velocity, temperature and wind Unit switchable for wind velocity, temperature and wind Color:As Shown Material:plastic Package Contents: 1 * BT-846A Digital Anemometer 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.