18x18x2 Pleated MERV 13 Air Filters 3 Pack cloning-and-seed-starting Duct Opening: 8” | Length:

Duct Opening: 8” | Length: 20" | Airflow Rating: 770 CFM | Carbon: Australian RC412 at 1200+ IAV | Thickness: 38mm

The thin shutter blades automatically open when the duct fan runs and closes when not in use

14” deep

Hanna Instruments Direct Soil HALO pH Electrode gives you the ability to measure

18x18x2 Pleated MERV 13 Air Filters 3 Pack cloning-and-seed-starting Duct Opening: 8” | Length:Nordic Pure MERV 13 Pleated AC Furnace Air Filters provide exceptional filtration for both home and commercial environments. Each time air passes through a Nordic Pure pleated furnace air filter, lint, dust, pollen, bacteria, pet dander, dust mites, mold spores, smoke particles, virus carriers, coughs and sneezes, smog, allergens and other contaminants are removed. MERV 13 furnace filters are comparable to HVAC filters with the rating of MPR 2200