The air-curtains are meant as an air defence for the industrial doors of warehouses, workshops, hangars and garages. They can be easily and quickly installed also in inner rooms requiring a different temperature: their high performance and their simple and strong structure make them the most appropriate equipment for this kind of fittings. These barriers are meant to work in dry rooms with a temperature from – 10°C to + 40°C, and to treat clean air without dust, chemical vapours, oily mist or other impurities. The air-curtain barrier is a real invisible door able to keep hot, cool and clean air efficiently inside the room. Moreover, it prevents winter cold air, summer heat and humidity, smog, dust, smoke, unpleasant or harmful smells and insects from entering the room.