16_1/2x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow Strong Elements Grow is a high

Elements Grow is a high nitrogen formula developed to encourage vigorous stem and leaf growth

Heavy duty construction with galvanized steel

Optimize Coverage - 3ft × 3ft

Clay Pebbles size 4mm-20mm

Powder coated steel guards for increased durability and corrosion resistance

16_1/2x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow Strong Elements Grow is a highNordic 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