16x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack Drying Racks The fan can run continuously

The fan can run continuously or on a timer to start and stop when you need it to

Atomic Root Powder is our unique root-enhancing formula made to grow and maintain a massive healthy root system throughout the growing season from start to finish

100-999: 1 µS/ppm

it runs quieter and cooler than any other ballast we have ever made

Power Supply: 100 - 150W

16x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack Drying Racks The fan can run continuouslyImportant 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 16x20x4 filter