Acoustic louvres prevent the transmission of sound into environment that accompanies air supplied from the outside. In order to dampen the sound, sound insulation material that is of 50 kg/ m³ density and perforated sheet metal of Ø5 mm perforation is used. On request, fly wire can also be installed to prevent entry of foreign particles. The product casing and blades are manufactured from galvanized sheet metal. As an option aluminium or stainless steel can also be used in manufacturing the louvres.