The filtration has multiple layers, usually composed of a combination of various filter materials, which helps capture particles of different sizes and supports air purification. Odorless design: the filter materials are treated so that they are unlikely to produce unpleasant smells during operation, helping to maintain natural air. Electrostatic mechanism assistance: some filter materials use an electrostatic electret process, which can help adsorb even smaller suspended particles. Good dust-holding capacity: the multi-layer structure can accommodate more dust and particles, which helps extend the filter's service life. Air Purifier Filter 5440i 5410i 5240i 5210i Compatible ,Compatible for Blueair， 5400i 5200i Replacement Filter Element for Air Cleaner Parts, Manufacturer: YLxshop