[EFFECTIVE FILTRATION]: HAPF600 filter replacement set contains 4 True HEPA filter, helps you absorb the suspended with microns effectively, the 4 included carbon filter's thick fits perfectly into the holding tabs on this "B" style HEPA filter. Combined use provide you higher filtration efficiency, longer use time, reduce unwanted odors in your living spaces, increased air quality enhances your indoor environment especially during this period of work . [PREMIUM QUALITY]: Fits for air purifier filter replacement hapf600 is made of high-strength and non-woven fabric and pre-filter is full of activated carbon, adopt advanced lower energy consumption and well test by the manufacturer. Extend service life and save your money [PERIODIC REPLACEMENT]: 4 pack of HAP600 replacement filter available for your time replace. Size: hapf600 hepa filter 10.0 x 6.8 x 2.1Inch; pre-filter 9.2 x 5.9Inch. NOTE: Recommended to replace the filter every 3-6 months, extend the service life of the air