21x21x1 MERV 8 AC Furnace Filters 6 Pack sprayers-and-wands They have a higher blue

They have a higher blue spectral ratio enhancing Veg and growth

Widely used in agricultural and horticultural application

so it does not have to be mixed with a "spreader-sticker" like the gallon size

baby's breath

or with a 2' T5 fluorescent lighting system (the 8 lamp fixture fits perfect

21x21x1 MERV 8 AC Furnace Filters 6 Pack sprayers-and-wands They have a higher blueNordic Pure MERV 8 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 and other contaminants are removed. MERV 8 furnace filters are comparable to HVAC filters with the rating of MPR 800. While different companies use different scales to measure the air filters