The high quality bearings in the Testo 417 Vane Anemometer yield nearly "friction-free" rotation for direct measurement of air velocity with an NTC sensor used to determine air temperature. The vanes cover all the measured area - no airflow is lost between the vane and outer ring. The 4" head averages true flow over its entire area, not just responding to local stray eddies. Just input the duct cross-sectional area (from 0.2 sq. in. to over 100 sq. ft.) to see accurate, real-time CFM calculations. Simply toggle between velocity, CFM, and temperature readings on the clear, backlit display.
Flow direction is indicated by an arrow in the display. timed or multi-point averages are easily accomplished with all parameters and calculations. Min-Max values can also be displayed. The"Hold" function freezes current readings in the display making data recording easy. Can use real-time or average CFM, velocity, temperature. True velocity measurement - no air density correction required. The Testo 417 as a simple one hand operation style and is easy to carry and operate.