The use of a device for connecting a pipeline to a counter piece for the conveyance of hydrogen gas, which device comprises an end portion of the pipeline and the counter piece, - the pipeline having a thickening in the end portion which adjoins a first outlet opening of the pipeline, which thickening has a cross-section (dv) which is extended with respect to the remaining end portion, - the thickening having a first sealing surface surrounding the first outlet opening, which first sealing surface points towards the first outlet opening and is in the form of a truncated cone or a spherical layer and tapers towards the first outlet opening, - the counter piece having a second sealing surface that surrounds its second outlet opening, which second sealing surface is in the form of a cone, the first and the second sealing surface being formed complementarily to one another and being arranged such that they interact in the manner of a seal, and such that the thickening plunges at least partially into the cone, - the thickening having a first support surface which points away from the first outlet opening and which projects radially over the end portion, - the device containing a clamping means which engages onto the counter piece and onto the first support surface such as to transfer force in order to press the pipeline substantially in the axial direction with its first sealing surface against the second sealing surface of the counter piece, a resulting seal between the first and the second sealing surface being gastight and a loss of the sealing function being avoidable in interaction with very low temperatures and high pressures upon contact with the hydrogen gas by the first and the second sealing surface being made of metal, the choice of material for the device being matched to the hydrogen gas. - the pipeline having a thickening in the end portion which adjoins a first outlet opening of the pipeline, which thickening has a cross-section (dv) which is extended with respect to the remaining end portion, - the thickening having a first sealing surface surrounding the first outlet opening, which first sealing surface points towards the first outlet opening and is in the form of a truncated cone or a spherical layer and tapers towards the first outlet opening, - the counter piece having a second sealing surface that surrounds its second outlet opening, which second sealing surface is in the form of a cone, the first and the second sealing surface being formed complementarily to one another and being arranged such that they interact in the manner of a seal, and such that the thickening plunges at least partially into the cone, - the thickening having a first support surface which points away from the first outlet opening and which projects radially over the end portion, - the device containing a clamping means which engages onto the counter piece and onto the first support surface such as to transfer force in order to press the pipeline substantially in the axial direction with its first sealing surface against the second sealing surface of the counter piece, a resulting seal between the first and the second sealing surface being gastight and a loss of the sealing function being avoidable in interaction with very low temperatures and high pressures upon contact with the hydrogen gas by the first and the second sealing surface being made of metal, the choice of material for the device being matched to the hydrogen gas.