a second flow contour igv 2 which is situated relatively close to the inner bundle ib wherein the first flow contour igv 1 is fixedly connected to the second flow contour igv 2 by way of guide vanes va the axial fastening by way of the first fastening elements fe 1 of the low pressure insert lpu to the inner bundle ib is configured such that the second flow contour igv 2 is fixedly screwed to the inner bundle ib the first flow contour igv 1 is in this case fastened to the second flow contour igv 2 only by way of the guide vanes va the guide vanes va are in this case advantageously formed in one piece with the two flow contours igv 1 igv 2 said unipartite form may advantageously be realized by way of welding or else may be the result of a manufacturing process proceeding from a solid in the case of manufacturing from a solid use may be made of a cutting machining process or machining by way of spark erosion an alternative manufacturing method for the low pressure insert lpu is provided by the relatively new method of u201c additive manufacturing u201d for example laser sintering or selective laser.