Shutter Exhaust Fan, 406 mm /16inch with Temperature Humidity Controller, EC-motor, 1747 CFM, Variable Speed Adjustable Wall Mount Attic Fan, Ventilation and Cooling for Greenhouses, Garages, ShedsShutter Exhaust Fan, 406 mm 16inch with Temperature Humidity Controller, EC motor, 1747 CFM, Variable Speed Adjustable Wall Mount Attic Fan, Ventilation and Cooling for Greenhouses, Garages, Sheds Product Features New Version What are the differences between the new version and the old one? Firstly, in terms of material, the new model uses full metal material. The louvers, mesh cover, fan body, and even the connecting parts are all made of metal,