12x20x1 (11_1/2x19_1/2) Nordic Pure Tru Mini Pleat MERV 13 Air Filters 3 Pack
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. The increased pleats enhance efficiency without restricting airflow, saving money on HVAC maintenance and extending filter life.