The Oreck XL Professional Tabletop air purifier uses Truman Cell technology to capture dirt and allergens from the air that passes through the filter* A permanent pre-filter captures larger particles, including dust and hair from the air that passes through the filter. Simply wash the filter as needed and reuse. The air purifier's 3-speed motor provides versatility in the amount of air circulation* Use on high for powerful air cleaning, medium for normal use, and low for continuous, quiet operation. The Professional tabletop Purifier is recommended for use in a 10'x10' room. Because this model is factory reconditioned, it comes with a 1-year limited warranty.