Abstract: An attachment element for assembly on a tubular element including an upper assembly sheet metal which includes in its outer end a transversal, upward directed mounting flange in relation to the assembly sheet metal which includes a cut out geometry, a lower sheet metal, a spacer element which link the upper assembly sheet metal together with the lower sheet metal in its interior ends and the spacer element includes attachment devices provided on both sides of an abutting section of the tubular element. The spacer element includes a wavelike geometry design which form the abutting section and the attachment devices. A galvanized barrel nut barrel nut including a barrel with a first and second interior diameter is also disclosed.