12x20x 1/2 Half Inch Ring Panel MERV 12 Furnace Air Filters 6 Pack meters-&-solutions They can be located outside

They can be located outside the grow room and a run of ducting can be extended from them into the room to extract the air and filter it

Eight speed options are available with power switch

The ionization tubes should be inspected and replaced periodically per the manufacturer's recommended schedule

Put it all together

Dimensions   45

12x20x 1/2 Half Inch Ring Panel MERV 12 Furnace Air Filters 6 Pack meters-&-solutions They can be located outsideNordic Pure Half Inch Ring Panel AC Furnace Air Filters consist of an internal frame bonded between flat layers of two different types of electrostatically charged HVAC furnace filter media. The first layer is a high capacity, polyester filter material which acts as a pre filter, capturing large airborne particles. The second, more efficient, layer is a MERV rated smooth poly blend filter material. The electrostatic charge works as a magnet to draw in