The 12" High-Output In-Line Duct Fan is powerful enough to air cool several lights connected by ducting, powerful enough to extract odor and heat from your room, and can be used for filters, intake, or exhaust. The 12" High-Output In-Line Duct Fan is powerful enough to air cool several lights connected by ducting, powerful enough to extract odor and heat from your room, and can be used for filters, intake, or exhaust. Keep your growing environment in balance by ensuring you have proper ventilation.