15" x 20", Purple, Ultra Allergen Filtrete Filter, The Filtrete&tm. Ultra Allergen Filter Outperforms All Other 1" Filters, 90% Effective At Capturing Large Allergens Like Mold & Pet Dander, Captures Micro Allergens Like Dust & Smoke, Also Captures Bacteria & Particles That Can Carry Viruses. MPR Rating 1500, Filter Lasts For 90 Days, Color Purple