20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 6 Pack New-releases CNS17 Grow formula also combines

CNS17 Grow formula also combines high levels of calcium with sulfates and phosphates to guarantee a balanced spectrum of plant nutrients

Requires only pliers or crescent wrench to assemble

2 flotation disks

CO2 (PPM) sensor and photocell to create the perfect all-in-one environmental sensor

20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 6 Pack New-releases CNS17 Grow formula also combinesImportant 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