For Blueair 500 600 Series: This filter is compatible with Blueair Classic 500 and 600 series air purifiers, including models 501, 503, 510, 550e, 555eb, 601, and others. Excellent Performance: The filter provides efficient filtration, capturing 99.97% of airborne particles as small as 0.3 microns using micro and macro pores. Practical and Powerful: Designed for effective and reliable air filtration, this filter is ideal for individuals sensitive to airborne particles. Safe Use: The filter does not release harmful substances, ensuring safe operation and promoting healthier indoor air. 3-Piece Set: This package includes 3 replacement filters. For optimal performance, replacement every 3 to 6 months is recommended, providing sufficient supply for approximately one year. Item Type: Air Purifier Filter Material: High-efficiency particulate air filter, cotton Package List: 3 x Air Purifier Filter Note: 1. For best results, replace the filter every 3 to 6 months. Installation is simple and requires no tools. Filters are disposable. 2. To ensure compatibility, please verify the part number and dimensions of your current filter before purchase.