Hencolin are a top one-stop service company with social consciousness to improve air and environment quality. With over 20 years industry experiences, we focus on providing and manufacturing all series of the best air filter products and technical supports to serve customers needs. We are ISO 9001:2015, UL900 and Eurovent Certificated Company. Hencolin's primary and medium filters are tested under ASHRAE 52.2-1999 standard (EN 779:2002 standard is also available ). Each HEPA filter will be scanned to detect possible leaks and filter performance, such as initial pressure drop and filter efficiency.