Improve air quality in the grow area with GrowBright duct filters. Dual-layer design keeps contaminants out with minimal airflow restriction. The outer screen catches bugs and larger particles while the inner activated-carbon lined layer traps finer particulates such as dust, spores, and pollen. GrowBright duct filters are also great for keeping debris out of air-cooled reflectors. Filters install easily over duct/flanging and secure tightly with velcro fasteners.