Made of HEPA filter paper, the purification efficiency up to 99%, the air is healthier. They are easy to remove and replace as part of routine maintenance. The filters help maintain the cleaning performance of the DYSON DC19 DC20 DC21 DC29 vacuum cleaner, while reducing the infiltration of dust, pollen and other allergens into the air you breathe. To keep your vacuum cleaner operating at peak performance, please replace your filter every 2 to 3 months. Package includes: 2 washable HEPA filters for Dyson DC19 DC20 DC21 DC29; 2 pre-filters for Dyson DC19 DC20 DC21 DC29. How to clean the filter: 1. Remove the bin by pressing the release button. - Open the bin door to empty it. 3. Press and lift the filter or release tab. 4. Remove the filter by grasping the yellow tab. 5. Tap the filter against the dustbin. 6. To reinstall the filter, press the metal filter lever, with the side of the filter and push the filter down, the filter door will not close if the filter is not installed