The Alen HEPA-Pure Filter combines three layers of filter technology to remove dust, pet dander, mold spores and pollen from your indoor air. Comes standard with the Alen A250 HEPA Air Purifier, the Alen HEPA-Pure Filter combines three layers of filter technology to purify and freshen the air in your home. Polluted air first passes through Alen's washable Pre-Filter to capture large particles, extending the life of the filter. In the second layer, air moves through a unique, electrostatically charged HEPA type material that attracts and captures dust, pollen, pet dander, mold spores and other airborne pollutants. In the final layer, clean air passes through a layer of Alen's Activated Carbon, reducing light odors and chemicals commonly found in the air from cleaning products, smoke, cooking, pets and various other household materials.