For ventilation of enclosed spaces that need to be protected against the spread of fire and smoke. Prevents heat build-up through constant air exchange. Fire resistance class F30 to F120 in accordance with DIN 4102. Maintenance- and inspection-free, no moving parts. Resistant to moisture, largely to oils, petrol and weak acids. Extremely simple installation. Use in individual cases on the basis of a project-related type approval (vBG).