Filters help maintain the cleaning performance of your Dyson DC19 DC20 DC20 Pre vacuum cleaner, while reducing the infiltration of dust, pollen and other allergens into the air you breathe. The 2-in-1 blue rear-mounted Dyson vacuum cleaner filter is The Dyson filter is perfect for pet owners. The Eco-Ready, anti-allergy, and Power filtration functions will keep your home clean. For best results, we recommend replacing the filter every 2-3 months for best performance.