20x23x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack Grow Light Ballasts Whole-house filter or stand alone

Whole-house filter or stand alone (with optional garden hose connection kit HL26010)

Carbon Quantity x Carbon Quality = Filter Capacity

but they also eat aphids

- Includes Vitamin B1 to ease shock and stress on plants

20x23x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack Grow Light Ballasts Whole-house filter or stand aloneNordic Pure Custom MERV 13 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