17x27x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack Air Purification With a maximum water holding

With a maximum water holding capacity of 60% there is no need to add perlite

Hang the BlackBird at 20–24 inches above the canopy for flowering

Thoroughly wet all infected areas

With its highly reflective hammertone specular construction

Directs light down in a focused pattern

17x27x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack Air Purification With a maximum water holdingNordic Pure Custom MERV 8 Plus Carbon air filters are made based on the actual measurements so be sure to measure your current filter to get the EXACT dimensions before ordering. As with all Nordic Pure filters, the effective life of your filter depends on the environment in which you live. We recommend changing 1 and 2 filters every 30 90 days. Our 4, 5 and 6 inch thick filters could last up to 6 months. EXACT MEASUREMENT: Furnace and air condition