Constructions and construction elements not of metal, namely, framework, door frames and window frames, bridges, stairs; constructions and construction elements of concrete, namely, sheets, plate, pylons, formworks, concrete pavements, concrete blocks; prefabricated concrete elements for the building industry and for public or private works, civil engineering and agricultural engineering, namely, prefabricated bridges, parts of prefabricated bridges, prefabricated walls; transportable non-met...