20x20x4 Purple Filtrete Filter

The Filtrete, 20 x 20" x 4", Allergen Reduction Filter, 3 Month Filter, For Housing Units Accommodating 4" Nominal SizeFilters & Is For Residential Use, Electrostatically Charged, Attracts & Captures Particles Like Pollen, Mold Spores, & Dust Mite Debris, MPR Rating 1750, Lasts Up To 12 Months.