Filtrete 20x25x4 Slim Fit MPR 1550 Air Filter, made by 3M, helps capture unwanted particles and allergens from your household air to contribute to a clean home environment. Designed with exclusive Filtrete 3-in-1 technology, including a high MPR 1550 and MERV 12 rating, your AC filter will help pull and capture countless microparticles – such as pet dander, smoke and smog – while letting cleaner air flow through. This air filter captures up to 50% of small particles (1), like bacteria and particles that carry viruses, to help make your air cleaner. Your Filtrete Filter will also capture large particles, including lint, pollen and household dust. Use a 12-month 4-inch home HVAC filter in your compatible furnace, air conditioner or HVAC system. For optimal performance of your HVAC system, change your 4-inch furnace filter at least once per year. Fits systems calling for a filter thickness of 3.75" and larger. Filtrete Brand is North America’s most trusted brand of HVAC Filters (2). (1) % captured is based on ASHRAE 52.2 testing for 0.3 to 1 micron particles from the air passing through the filter, which relates to HVAC industry standard efficiency testing. (2) Based on 2024 Sago US Brand Health Survey of Residential HVAC Air Filters