Nedco's metal ducts are made of Galvanised steel. They are 0.5 mm thick. Nedco keeps standard 1 metre lengths in stock. Contact Nedco for longer lengths. We will provide you with prices on request. Due to the simple assembly, these ducts are ideal for use in both visible and concealed locations. These metal ducts can be used in: schools, hotels, restaurants, public buildings, shops, etc.