Air permeability also can be used to provide an indication of the breathability of weather-resistant and rainproof fabrics, or of coated fabrics in general, and to detect changes during the manufacturing process. In specialty, industrial and military applications, it can play a vital role in protection. In every market, satisfying the demands of consumers and producers requires ways to accurately and repeatably test material air flow. https://www.testerinlab.com/products/yjfqcl/1020.html