12_3/4x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack nutrient-combo beds and most other growing

beds and most other growing techniques

5 Liters (1

Root Royale Hydro Clay Pebbles are 16-20mm in size

and completely water-resistant

12_3/4x21x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack nutrient-combo beds and most other growingNordic 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