21_1/2x23_3/8x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow Light Ballasts A-OK Starter Plugs come labeled

A-OK Starter Plugs come labeled with instructions in a shrink-wrapped sheet that fits a standard 10 x 20 tray (flat)

This increase in availability of electrons promotes efficient absorption and uptake of nutrients

Blend 99 is a “clean slate” growing media

000 Product Height (in): 2

21_1/2x23_3/8x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow Light Ballasts A-OK Starter Plugs come labeledNordic 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