This is a High Quality Washable & Reusable Replacement Micro Allergen Pre & Post-Motor HEPA Filter. Fits ALL Dyson DC17 models. Compare to Dyson Pre-Motor Filter Part # 911236-01 & Post Filter Part # 911235-01. Highly recommended to replace your filter every 3 to 6 months for optimal use and performance of your Dyson Vacuum Cleaner. Absolutely Essential For Allergy Sufferers! Designed & Engineered By Crucial Vacuum. This is a generic product designed and engineered in the United States by Crucial Vacuum. This is not a Dyson® OEM product and is not covered under any Dyson® manufacturer's warranty. The Dyson® brand names and logos are the registered trademarks of their respective owners. Any use of the Dyson® brand name or model designation for this product is made solely for purposes of demonstrating compatibility.