The CFM Master II is a convenient, portable service tool for the hvac technician, says the company. With its one-piece design, the DCFM8906 combines accurate airflow measurement with ease of use, the manufacturer says. The instrument displays temperature, cfm, fpm, mph, kph, and knots. Other features include single-point average, multi-point average (up to 8 points), minimum-maximum, and data hold.