20X20X1 Air Filter, Filtrete Healthy Living Ultimate Allergen Reduction, MPR 1900, (3-Pack) Electrostatic High Performance Air Filter. Helps Promote Healthy Home by reducing DUST, ALLERGENS, BACTERIA & VIRUSES. Each Filter lasts upto 3 months. Captures large particles like household dust, pollen, dust mite debris, mold spores & pet dander. Captures small particles like smoke, smog, bacteria, and particles that can carry viruses and odors.