The DCFM8906"is a professional-grade vane anemometer that can not only measure air speeds exiting an HVAC/R system's or blower's grille or register, but also convert those readings to airflow volume measurements. The conversions are possible because the meter makes it easy for an installer or repairman to enter the free area dimensions of his system's output duct work. The meter can record air speed readings at one point or multiple points for up to two hours and convert those readings into displays of average, minimum and maximum air speed or airflow volume. The unit can hold measurements made in the dark for later viewing in a brighter area. It also measures ambient air temperature and displays it simultaneously with air speed or airflow volume on a large front-panel LCD. The DCFM8906"can display its air speed and airflow volume measurements in Imperial or metric units and its temperature measurements in degrees Fahrenheit or Celsius. A 20-minute auto power off function (which can be disabled to enable long-term recordings of air speed) helps extend battery life. The DCFM8906"is powered by one 9V battery (included). Features & Benefits : Displays CFM, CMM, FPM, temperature and knots Measures and displays air speed and airflow volume in Imperial or metric units Measures air temperature and simultaneously displays in °F or °C Single and multi-point average Min/Max memory Data hold °F/°C switch One-handed operation Records average, minimum and maximum air speed at a single point or multiple points Auto power off RS-232 output CE and RoHS approved Applications: Ideal for measuring airflow speed and volume output of exhaust fans and blowers. Specifications : Airflow Volume Measurement Range: 0 to 99,999 CFM or CMM Airflow Velocity Measurement Range: 80 to 5900 ft./min (0.4 to 30 m/sec) Airflow Measurement Accuracy/Resolution: ±3%/1 ft./min (10 mm/sec) Temperature Measurement Range: 14° to 122°F (-10° to 50°C) Temperature Measurement Accuracy/Resolution: ±2°F (±1°C)/0.1° Dimensions: 7 x 2.5 x 1.75 in. (183 x 76 x 45mm); Vane diameter: 2.8 in. (70mm) Display Size: 1.25 x 1.625 in. Power Source: 1 ?9V? battery (included ) Includes : Molded hard case Instruction Manual Battery- SKU: GNRL132