16x20x4 (3 5/8) Pleated MERV 13 Air Filters 1 Pack AIR FILTER BOXES manufacturing and others require 99

manufacturing and others require 99

Compatible with most major brand ballasts and reflectors including Hypotek™and Grow1™

When mixing with any phosphorus additives (like Elite 91 FLOWERS)

leaving your plants clean and strong

16x20x4 (3 5/8) Pleated MERV 13 Air Filters 1 Pack AIR FILTER BOXES manufacturing and others require 99Important 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 16x20x4 filter