BestAir Extreme Allergens, Pollen & Dander Air Cleaning Filter for Aprilaire/SpaceGard & Lennox - 20 X 25 X 6 MERV 11. Optimized For Aprilaire SPACE GARD 20 x 25 x 6 (actual 19 ¾ x 24 ¼ x 6”) Fits: Aprilaire SPACE GARD 2200, 2250 (201); Lennox PMAC-20C 24" – includes cardboard frame Our specialized filtration media has the most effective combination of particle capture rate, with minimum pressure drop, ensuring the best overall performance of your HVAC system and particle capture rate to clean the air. This media has special emphasis on particulate size that captures most airborne allergens. Made in the USA