1APPLICABLE MODELS: This filter element is suitable for Blueair Pro M (1 filter), for Blueair Pro L (2 filters) and for Blueair Pro XL (3 filters) air purifier models. 2HIGH EFFICIENCY: Effectively captures harmful ultrafine pollution particles as small as 0.1 microns and captures up to 99.97% of air pollutants from the air. 3AIR OPTIMIZATION: Activated carbon granules reduce smoke, odors and harmful VOCs, optimize room air quality and ensure a healthy living environment. 4FOLDABLE DESIGN: The air filter element is foldable design, which is easy to unfold and use, and it can be folded and stored to save space when not in use. 5APPLICABLE SCOPE: Ideal for people allergic to dust, pollen, pet hair and dander, this filter element is ideal for home or office use to ensure human body health.