20x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack Hydroponics It has a safety valve

It has a safety valve and pressure indicator to avoid excessive pressure

Enhance trichome development increase yield with the state-of-the-art ILUMINAR Lighting iLogic™8 UV+Far-Red

EC or TDS values directly in your reservoir

A VE115 3cfm (BVVVE280) vacuum pump is recommended for this system

#43905-1) and has complied with all EPA regulations for the continued use of IBA in the product

20x20x4 (3 5/8) Pleated MERV 7 Air Filters 6 Pack Hydroponics It has a safety valveImportant 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