The AN300-NIST is a Large Vane CFM/CMM Thermo-Anemometer. This meter 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. Complete with 4 AAA batteries and hard carrying case. Includes certificate traceable to NIST.