A connecting device comprising: a tubular counter part; a fixation member; and a system comprising a tubular nozzle and a flexible conduit tube, wherein the system is configured for use in exhaust systems, wherein the flexible conduit tube comprises: a bellows member, an outer flexible member which is provided on the outside of the bellows member, a cap having an annular shape and being provided on the axial end portions of the flexible conduit tube, and a sleeve member having an annular shape, wherein the cap has towards its inner end a bending section such that a portion of the cap is extending in a radial outward direction so that the inner end is placed on the radial portion of the cap, and the cap is contacting the outer flexible member on an inner surface, wherein the sleeve member is provided on the axial end portions of the flexible conduit tube and whereas the nozzle is directly connected to the bellows member and/or the sleeve member, wherein the tubular nozzle is connected to the flexible conduit tube in a gas proof manner and extends in a funnel shape on its end being opposite of the end connected to the flexible conduit tube, wherein the cap and the nozzle are provided in one piece, whereas the funnel shaped portion of the nozzle extends in the shape of a truncated cone in a radially outward direction, wherein the tubular counter part is configured to connect the system, and comprises a connecting portion which is contacting with the funnel portion of the nozzle at least section wise, wherein the fixation member is in contact with the counter part and the nozzle so that the system is fixed by form fit and/or force fit, characterized in that the connecting portion of counter part has at least in a section a convex shape, in the shape of two truncated cones which are joined at their base. a tubular counter part; a fixation member; and a system comprising a tubular nozzle and a flexible conduit tube, wherein the system is configured for use in exhaust systems, wherein the flexible conduit tube comprises: a bellows member, an outer flexible member which is provided on the outside of the bellows member, a cap having an annular shape and being provided on the axial end portions of the flexible conduit tube, and a sleeve member having an annular shape, a bellows member, an outer flexible member which is provided on the outside of the bellows member, a cap having an annular shape and being provided on the axial end portions of the flexible conduit tube, and a sleeve member having an annular shape, wherein the cap has towards its inner end a bending section such that a portion of the cap is extending in a radial outward direction so that the inner end is placed on the radial portion of the cap, and the cap is contacting the outer flexible member on an inner surface, wherein the sleeve member is provided on the axial end portions of the flexible conduit tube and whereas the nozzle is directly connected to the bellows member and/or the sleeve member, wherein the tubular nozzle is connected to the flexible conduit tube in a gas proof manner and extends in a funnel shape on its end being opposite of the end connected to the flexible conduit tube, wherein the cap and the nozzle are provided in one piece, whereas the funnel shaped portion of the nozzle extends in the shape of a truncated cone in a radially outward direction, wherein the tubular counter part is configured to connect the system, and comprises a connecting portion which is contacting with the funnel portion of the nozzle at least section wise, wherein the fixation member is in contact with the counter part and the nozzle so that the system is fixed by form fit and/or force fit, characterized in that the connecting portion of counter part has at least in a section a convex shape, in the shape of two truncated cones which are joined at their base.