18x24x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 6 Pack tents-&-tarps light proof

light proof

and the locking hook keeps the blade closed when not in use

Compatible with all Hydrofarm heat mats

Provides balanced calcium and nitrogen ratios

it can also be used as a powerful foliar spray as well

18x24x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 6 Pack tents-&-tarps light proofNordic Pure 18x24x4 MERV 12 Pleated Plus Carbon air filters are made of a dual material where the MERV rated material has been fused together with a carbon layer. This results in less flow restriction and 33% more surface area for cleaner smelling air. It will help eliminate unwanted odors as well as trap most airborne dust and particulate matter for fresh, clean air. Odorous gases and vapors (VOC) are attracted to and held by the activated carbon