18x20x1 MERV 6 Poly Green AC Furnace Air Filter 2 Pack – Captures Dust/Pollen
There is an airflow direction arrow on the side edge of your Nordic Pure pleated air filter. For air filters with carbon added the carbon is on the air exit side. These generally look like large vents, but the air flows into them, rather than out of them when the heating or cooling system is blowing air.