The Triplett CFM400 4" Large Vane CFM/CMM Thermo-Anemometer measures Air Velocity up to 5900ft/min (30m/s), Air Flow (Volume) to 99999 CFM/CMM, and Air Temperature 140°F/60°C) for use in HVAC system installation and maintenance, cleanrooms, kitchen exhaust systems, wind power monitoring, construction, sailing/boating, vehicle aerodynamics and many other applications. The CFM400 measurements are displayed on a dual backlit easy-to-read LCD display. The CFM400 min/max recalls highest and lowest readings plus Multi-Point Average and Timed Average modes. The CFM400 data hold freezes the reading on the display when taking measurements in areas where the display cannot be easily viewed. The CFM400 auto power off (with disable) function conserves battery life. 1 year warranty.