Filtrete 20x20x1, AC Furnace Air Filter, MPR 1000, Micro Allergen Defense, 4-Pack exact dimensions 19.69 x 19.69 x 0.81Opt for a Filtrete Allergen DefenseAir Filter to transform your central heating and cooling system into a whole-home air filtration operation. This no-nonsense filter helps capture varying sizes of particles, from the large lint, pollen, dust and pet dander to the microscopic smoke and smog.OUTPERFORMS FIBERGLASS, WASHABLE AND NON-ELECTROSTATIC 3-month pleated 1 in. home air filters for your furnace, air conditioner or HVAC systemDESIGNED WITH EXCLUSIVE Filtrete Brand 3-in-1 technology from 3M to trap unwanted air particles while letting cleaner air flow throughATTRACTS AND CAPTURES particles such as lint, pollen, dust, pet dander, smoke and smog1000 MPR has a rating of MERV 11The higher the MPR, the more microparticlessuch as pollen, pet dander, smoke, bacteria and virusesyour filter will capture from the air passing through it