Five-layer filter replacement keeps the Lorell HEPA 420 Air Purifier running efficiently. Pre-filter removes hair/dust and large pollutants. The anti-bacteria PET layer removes large particles and protects the HEPA filter. HEPA filter removes up to 99.97 percent allergens and germs as small as 0.3mm. Activated carbon layer absorbs odors, formaldehyde, volatile organic compounds (VOCs) and other pollution. Nylon mesh filter protects the other side of the HEPA filter. Depend on this True HEPA 420 Air Purifier Filter Replacement 5-Layer for higher air quality. More from the Manufacturer This product ships in approximately 1 days