The Extech AN100 CFM/CMM Thermo-Anemometer can simultaneously display Air Flow or Air Velocity plus Ambient Temperature. Easy to set area dimensions (cm2) are stored in the meter's internal memory for the next power on. Additional features include: 20-point average for Air Flow and 3% velocity accuracy via low friction 2.83 in. D (72mm) ball bearing vane wheel on 3.9ft (120cm) cable.