20x28x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack special-order Rain-Fast After 24 Hours –

Rain-Fast After 24 Hours – Stays effective after it dries

Enhances plant functions at the foliar level and the root zone in both soil and soilless substrates

Derived from a natural source

These professionally formulated nutrients provide high performance ingredients in a simple to use program

it is crucial to maintain proper suction

20x28x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack special-order Rain-Fast After 24 Hours –Nordic 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