Simply attach the hood and rotate the vane sensor to point into the direction of flow. The hood is also suitable for measuring ventilation flow rates for both supply and extract air. This aircone hood allows for "one-shot" measurements of air volume flow at grilles, diffusers and air valves and is self sealing for leak tight readings. The TSI LCA301 airflow anemometer kit comes supplied with a square Aircone Flow Hood that can be attached to the vane sensor. This is the perfect device for HVAC commisioning at grilles, ducts and diffusers. A large LCD display allows air velocity or air volume flow measurements to be quickly and clearly shown in either metric or imperial mode. An advanced feature of this airflow anemometer is the built-in compensation factor that helps the instrument overcome the friction of the bearings at lower velocities To ensure accuracy the LCA301 airflow measurement device has a self-diagnostic function to automatically test that the unit is working correctly. The LCA 301 anemometer allows the user to traverse large grilles and ducts in one sweep and have the average air flow or air velocity value automatically displayed. The Airflow LCA301 Rotating Vane Anemometer with Aircone Flow Hood Kit from TSI Instruments is a lightweight, simple to use device that provides accurate and reliable air flow and velocity readings every time. TSI Airflow LCA301 Rotating Vane Anemometer Kit