An exhaust filter is an essential component to a ventilation system. The ventilation system in your grow room will consist of Inline Fan and Carbon Filter. All Fan and Filter Kits are available in five of our best styles in our store. The kit styles have: 4" Kits, 6" Kits, 8" Kits, 10" Kits, 12" Kits.The main function of Fan is to grow Medicinal Plants for indoor ventilation . Our Filter is to prevent odors .