The Extech 407119 Heavy Duty CFM Hot Wire Thermo-Anemometer is a reliable and versatile tool for measuring air flow, air velocity, and temperature. This thermo-anemometer is designed for professionals in HVAC, industrial, and ventilation applications, offering accurate measurements and a range of useful features.The Extech 407119 features a telescoping probe that extends up to 3 ft, making it ideal for use in ducts and ventilating systems. This allows you to reach into confined spaces and access hard-to-reach areas for accurate measurements.With this thermo-anemometer, you can accurately measure air flow (CFM/CMM), air velocity, and temperature. The instrument provides instant readings of air flow and air velocity, allowing for real-time assessment of airflow conditions. The air flow measurement can also be displayed as an average value calculated from up to 20 individual measurements, providing a more stable and representative value over time.In addition to air flow and velocity, the Extech 407119 measures temperature, providing a comprehensive understanding of the airflow conditions. The instrument allows for simultaneous measurement of air velocity and temperature, offering valuable insights for airflow analysis and temperature control.The meter includes several additional functions to enhance functionality. The Data Hold function allows you to freeze the displayed reading for easy recording or note-taking. The Min/Max function enables you to track the minimum and maximum values over a period of time, providing valuable information about airflow fluctuations. The Auto Power Off feature conserves battery life by automatically turning off the meter after a period of inactivity, ensuring efficient use and extending the lifespan of the batteries.The Extech 407119 is equipped with a built-in RS-232 interface, enabling connectivity to external devices such as computers. With the optional Data Acquisition software and cable, you can record and analyze the measurements directly on a PC, expanding the capabilities of the instrument for data logging and analysis.