18x18x1 Pure Green Eco-Friendly AC Furnace Air Filters 24 PackPure Green Eco Friendly AC Furnace Air Filters by Nordic Pure are made from an environmentally responsible non woven, high loft, antimicrobial filter media. The MERV 6 rating has a lower pressure drop, minimizing energy consumption while maintaining a high dust holding capacity. As we continue to keep our eyes on media technology advances, our Pure Green media will be changing its appearance. Please expect the same quality and performance you have