The Meaco Deluxe 202 HEPA filter is guaranteed to provide you with the best air cleaning. To help fight against any allergic reactions to mould spores, pollen, dust, pet dander, the HEPA filter is ideal.The True HEPA filters conform to international standards and capture 97.3% of particles with a size of 0.3µm in diameter, complying to class E11. These filters are currently the best for humidifiers and cleaning the air. The charcoal filter is an active charcoal filter with 12-15g of charcoal to help remove odours.The HEPA filters come in a pack of three and last roughly 6 months. When they change colour from white to grey / dark grey, they must be replaced.If the plastic bag around the HEPA filters has been opened, this product cannot be returned for health and safety reasons.