: This filter is exclusively designed for the Levoit Core 400S Smart True HEPA Air Purifier to ensure the best performance. Search LRF-C401-P-GUS" for the official Levoit Core 400S 3-Stage Toxin Absorber Replacement Filter - : Three stages of filtration trap a wide variety of airborne contaminants, such as vehicle exhaust, smoke, and toxic compounds , : The Toxin Absorber Replacement Filter is equipped with an Efficient Activated Carbon Filter which helps to abosorb vehicle exhaust, smoke, and fumes perfect for people living in urban and industrial areas : Captures at least 99.97% of 0.3-micron airborne particles, while statically charged fibers trap viruses and bacteria - : This filter is made to last 6 12 months and easy to replace, so you don t have to worry about frequent and difficult replacements.