BestAir 12x20x1" Standard Pleated MERV 8 Air Filter. It is effective against bacteria, pollen, dust/lint, and mold spores. This filter reduces up to 75% of large airborne particles. The MERV 8 rating means it is third-party certified to effectively reduce common indoor air pollutants such as household dust, pollen, dander, and lint. MERV ratings provide a standard comparison of air filter performance. A higher MERV rating signifies greater efficiency and increased protection against airborne particles. The clay-coated filter frame and wire backing provide durability throughout the filter's life. Last up to 90 days.