Filtrete 20"x25"x4" Filtrete Ultra Allergen Reduction Deep Pleat Filter. It is a high efficiency filter that filters dust/lint, mold spores, bacteria, pollen, smoke, and viruses. It has a MERV rating of 12. This filter attracts and captures microscopic particles like bacteria, particles that can carry viruses and large particles like mold spores and pollen. It captures 97% of large airborne allergens, such as pollen, mold spores, and dust mite debris. The robust frame construction enhances quality and ensures high durability. Compatible with aprilaire, space-gard, trion, air bear, and honeywell systems. Electrostatically charged to attract and capture microscopic airborne particles.