The Airflow™ Instruments LCA301 and LCA501 Rotating Vane Anemometers measure air velocity, air volume, and temperature in English or metric units. The 4-inch (100 mm) head automatically averages velocity and volume readings, making the LCA301 and LCA501 essential tools for measuring unevenly distributed or fluctuating flows through heating and cooling coils, diffusers, grilles, and filters. Sweep mode quickly and reliably provides one averaged reading of velocity or volume over a large measurement area.