Circular in-line duct centrifugal fans, manufactured from high grade corrosion resistant pressed galvanised steel. All models are supplied as standard with a pre-wired junction box. All models include an enclosed type single-phase external rotor motor with factory matched backward curved non-standing impeller. Suitable for operating in temperatures –40° up to +60°. IP44, Class B insulation, and all motors include an internal safety thermal overload protection devise as standard. All models are fully speed controllable using either electronic or autotransformer voltage regulations controllers.