16x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 1 Pack Grow Strong Zippers are just as strong

Zippers are just as strong as ever

bloom more and have an increased yield while providing a nutritional boost of potassium and phosphorus

it also offers a propagation area for growing

they have a cotton lining

SUPERthrive® Pro-Tekt® is a nutritional supplement for plants that’s in an easy-to-use liquid concentrate that’s ideal for hydroponic use

16x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 1 Pack Grow Strong Zippers are just as strongImportant 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