Large Vane CFM/CMM Thermo-Anemometer. Measures Air Velocity, Air Flow and Temperature. Extech's Large Vane Thermo-Anemometer series allows for more precise readings on larger size ducts. Each meter simultaneously displays Airflow or Air Velocity and Temperature. Multipoint and timed average calculations. Min/Max, Data Hold, and Auto power off functions. Complete with four AAA batteries and hard carrying case.