20x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack Meters & Solutions A heating mat designed to

A heating mat designed to accelerate and improve the success of seed starting and germination

Helps stimulate flower development in the final bloom stage

is 100% biodegradable and is hand crafted in small batches

The controller also has the ability to simulate sunrise and sunset cycle from 10-60 minutes

Generate usable lighting and provide good light canopy penetration

20x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack Meters & Solutions A heating mat designed toImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. If you are replacing a 4 3 8 depth 20x20x4 filter