Casing made of aluminium profiles or galvanized steel Casing made from galvanized steel sandwich type with internal acoustic insulation 40 or 60 mm thick All panels can be registered External rotor motor protected through thermal contact or belt-driven 0-100% variable speed Very low noise level Executions and characteristics according to customer needs. There can be included filters of all the efficiencies, shutters, heat/cold elements, recuperators, etc.