16x21x1 MERV 7 Plus Carbon AC Furnace Filters 12 Pack sprayers The yellow LED indicator shows

The yellow LED indicator shows CO2 level equal or above 800ppm which means supplemental CO2 is in use

or any other type of growing media

or additives can be added if the grower desires different specifications

and increasing potency

Gladiator and 3

16x21x1 MERV 7 Plus Carbon AC Furnace Filters 12 Pack sprayers The yellow LED indicator showsNordic Pure pleated AC air filters are made of electrostatically charged synthetic materials that attract and capture most airborne particulates in your home or office. Each time air passes through a Nordic Pure pleated furnace filter, lint, household dust, pollen, dust mites, pet dander, baking flour, mold spores and other contaminants are removed. Our filter media prevents the growth of bacteria or mold, resulting in a much healthier living space.