20x25x5 (4 3/8) Lennox X6673_X6675 Replacement Odor Reduction Merv 8 Filter 2 PK
It can replace not only Lennox but Honeywell, Carrier, and Bryant air filters. Of course, this is just a list of the most well-known systems that use this size. There is an airflow direction arrow on the side edge of your Nordic Pure pleated air filter.