Cetatest 915 flow detector is used for volume flow test. The instrument is equipped with laminar flow components and differential pressure sensors. In the direct measurement mode, there is a pressure regulator inside, and the air flow enters the measured workpiece after passing through the measurement and test end; In the indirect measurement mode, the test end is located behind the tested workpiece. The specially designed test end can generate air laminar flow, and the test result (differential pressure) is directly proportional to the volumetric flow.