It is a glass wool board faced with aluminium foil on one side and black glass tissue on the other side or faced with aluminium foil on both sides. It is used for all the buildings that need ventilating and air conditioning ducts. Owing to its vibration absorbing performance, it is used for the buildings in which it is preferred that HVAC equipments run quietly. The duct is also used for multi storey buildings regarding to fire safety since it is noncombustible.