21_1/4x23_1/4x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow System/ Trays/ Reservoirs durability

durability

Rootshield Plus is also available in a wettable powder formulation

75 HP gear driven motor with variable speeds to provide unsurpassed power and adjustability

Hydrofarm's heavy duty measuring beaker offers easy-to-read

21_1/4x23_1/4x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow System/ Trays/ Reservoirs durabilityNordic Pure Custom MERV 12 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