20x20x4 (3 5/8) Pleated Air Filters MERV 13 Plus Carbon 6 Pack HVAC & HOME VENTILATION Two square obeservation windows on

Two square obeservation windows on the front door

This cord and its software

Multifaceted design provides superior light uniformity

economy and extend longevity

8 x Matrix Circulator | 2 1/4"

20x20x4 (3 5/8) Pleated Air Filters MERV 13 Plus Carbon 6 Pack HVAC & HOME VENTILATION Two square obeservation windows onImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. If you are replacing a 4 3 8 depth 20x20x4 filter