1.ISO, RoHS, SGS2. 2. high efficiency, low resistance 3 ages experiences HEPA series filter material or filter mediaAdopt high efficiency paper filter element, catechin, anti-sensitive, vitamin C, aromatics, active carbon, photocatalyst, cold catalyst, nano silver to make HEPA filters. It has the function to purify and absorb the odor substances, for example, ammonia, fluorine, formaldehyde, ...