16x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack ph-ec-tds-meters-and-solutions SupremeLux offers adjusted horticultural spectrum

SupremeLux offers adjusted horticultural spectrum in HID grow lamps

Young plants can grow in Turf & Surf for up to one month without adding fertilizers or nutrients

thick cell walls (this thickness provides pathogen resistance and strong stalks)

ideal color temperature

16x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack ph-ec-tds-meters-and-solutions SupremeLux offers adjusted horticultural spectrumImportant 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