Filtrete 20x20x1 MPR 1000 Air Filter, made by 3M, helps capture unwanted particles from your household air to contribute to a cleaner, fresher home environment. Designed with exclusive Filtrete 3-in-1 technology, including an MPR 1000 and MERV 11 rating, your AC filter will help pull and capture countless microparticles – such as pet dander, smoke and smog – while letting cleaner air flow through. Your Filtrete Filter will also capture large particles, including lint, pollen, mold spores and household dust. Use a 3-month pleated 1-inch home HVAC filter in your furnace, air conditioner or HVAC system. Four come in a pack, so keep some filters as backup, or use them in multiple areas. For optimal performance of your heating and cooling system or HVAC system, change your furnace filter at least every 90 days.(1) Based on the 2022 Ipsos US Brand Health Study of Residential HVAC Air Filters.