17_1/2x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack spl_allstate A common source of silicon

A common source of silicon is clay

A small efficient tool

This ancient source of plant food has proven itself over the ages to be an effective way to achieve a successful harvest

for less cost

Excellent PAR output (2100 µmol/s)

17_1/2x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack spl_allstate A common source of siliconNordic 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