Galvanized Box Fans.

Fiberglass nozzle
Galvanized balanced fan blade
Galvanized shutters with efficient centrifugal oper system.
This opener system allows the shutters to fully open as soon as the fan starts to turn. Air delivery normally lost due to dirty shutters or to hold shutters open is eliminated.

Take a look at the VAL-CO Recirculating Fan.

Galvanized Box Fans (type GB) available as 36"and 50"sizes with stainless steel blades.