16x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack controllers Available Phosphate (P2O5) 1

Available Phosphate (P2O5) 1

Hands-free monitoring and dosing of solution pH levels

bat guano and kelp meal

The lightweight aluminum handle quickly collapses down from 30-inches to 19-inches for easy storage

a 50 cube plastic insert and 50 ready-to-plant Root Riot™ Plant Starter Cubes

16x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack controllers Available Phosphate (P2O5) 1Important 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