21_1/4x23_1/4x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack Emitters The little holes on the

The little holes on the inside of the cartridge vary in size and quantity depending on the type of cartridge and oil that will be used

The Autopilot PX1 Digital Lighting Controller from Hydrofarm provides centralized

The Hydroponic Research Growth Chamber is a unique

Use with CO2 regulator and tank to evenly distribute CO2 to your grow area and plants

making it the best flower trimmer in the industry

21_1/4x23_1/4x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack Emitters The little holes on theNordic Pure Custom MERV 14 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