125mm CARBON FILTER EXTRACTOR FAN AND 5M DUCTING KIT, fresh kit for 175m3/hr, Ventilation is an important part of your hydroponic setup. It provides your plants with the ideal growing environment. Ventilating your growing area removes stale air that contains moisturefrom plant transpiration which can causeb disease and decay. correctly ventilating your growing area also removes any unwanted odours from watertanks ect, excess heat, and provides a continuous supply of fresh co2 - invaluable for your plants development.