GermGuardian® FLT5900 true HEPA genuine replacement J-sized filter is a multiple level cleaning system that includes a true HEPA filter, activated carbon filter and pre-filter seen that all help to improve indoor air quality. The true HEPA filter captures 99.97% of dust and allergens as small as 0.3 microns such as household dust, pet dander, mould spores and plant pollens. The activated granular carbon filter reduces odours from pets, smoking, cooking along with harmful doc's emitted from a variety of household products and chemicals. Finally, the pre-filter screen captures large dust particles and pet hair, extending filter life. It is recommended to use with the GermGuardian® AC5900CADR. The use of this genuine Guardian Technologies(TM) replacement part will maintain the product's performance and warranty.