The STA2 is a hot-wire Anemometer built for the HVACR professionals air balancing needs. The compact probe tip makes measuring air velocity directly in the duct a breeze. It's great for traversing a duct and automatically calculating cfm without the hassle and expense of a bulky hood. The 38 in telescoping probe's laser etched ruling and flattened edges allows techs to locate proper measurement points within a duct and ensures that the probe is properly aligned. This in-duct hot-wire Anemometer quickly calculates cfm from air velocity and free area. And with the intuitive interface, the STA2 makes it easy-to-capture the correct data.