GENUINE 4 IN 1 : Independent Pre-Filter, True HEPA Filter, Cold Catalyst and Activated Carbon Replacement filter for the PureMate PM 505 Air Purifier. Recommend replacing your filter every 4000 hours. TRUE HEPA TECHNOLOGY: Filters 99.97% of dust, pollen, smoke, odors, mold spores, and pet dander. These air filters catch particles as small as 0.3 microns and larger and filters air pollution of PM 2.5 (pollution rate) to help improve overall health ACTIVATED CARBON FILTER: True HEPA filters reduce unwanted odors in your living spaces. Perfect for pet owners, children, elderly, or for anyone wanting to improve air quality COLD CATALYST FILTER : The cold catalyst can absorb the formaldehyde. It has a very. strong ability to remove formaldehyde. Cold catalyst is another new type of air purification material after Photo catalyst air purification material. PRE-FILTER: Captures initial dust and allergen particles. BUY WITH CONFIDENCE: 100% Satisfaction guaranteed. If you need additional assistance, contact the helpful PureMate Support. For use with PM 505 Air Purifier but machine not included, Manufacturer: PureMate