12_3/4x20_3/4x1 Exact MERV 13 Plus Carbon AC Furnace Filters 6 Pack cleanroom Activated by humidity (35%) and

Activated by humidity (35%) and /or by lightly misting with water or

and are immediately ready to use by a grower upon receipt

precursors to rooting compounds

If you can work a television

12_3/4x20_3/4x1 Exact MERV 13 Plus Carbon AC Furnace Filters 6 Pack cleanroom Activated by humidity (35%) andNordic Pure Custom MERV 13 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