Airoclean 420 Max and Airoclean 420 XL offer commercial growers two ways to rid your grow areas of powdery mildew, mold, bacteria, and harmful pathogens. Both are designed with Airoclean 420’s patented Photocatalytic Oxidation process that destroys contaminants. HEPA filters simply trap and then release them back into your grow environment. Airoclean 420 releases no ozone or emissions and uses no chemicals. Made in the U.S.A.