The Filtrete 2200 Elite Allergen, Filtrete 1900 Ultimate Allergen, Filtrete 1500 Advanced Allergen, Filtrete 1250 Ultra Allergen and the Filtrete 1000 Micro Allergen reduction filters outperform all other 1" non-electrostatic filters (including 3-month pleated filters, washable and reusable permanent filters, and fiberglass furnace filters). Each filter lasts up to 3 months under normal use, and captures allergens both large and small, including dust, lint, pollen, pet dander, mold spores, smoke, smog, bacteria and particles that can carry viruses. They are also approved for use by the American Lung Association. The higher the MPR rating, the more effective the filter will be at capturing allergens.