PVC-coated fabric ventilation ducts are available in various inside diameter (I.D) sizes, lengths, and colors. These ducts are also available in a variety of shapes, including round, half-round, quarter-round, and ellipses. Typically, they are hung from a horizontal steel aircraft cable that runs through each end of the duct. In addition, a type of support system is usually fabricated... https://www.duletai.com/product/pvc-vent-duct-fabric/