Arrangement for connecting two tubular pipe elements (2, 3), in particular two pipeline elements, of equal external diameter or unequal external diameters, comprising: a hollow-cylindrical coupling device having a first hollow-cylindrical coupling-device part, which can be or is assigned to a first pipe element, and having a second hollow-cylindrical coupling-device part, which can be or is assigned to a second pipe element, which can be or is connected axially to the first pipe element, wherein at least one first form-fitting element is arranged or formed on the first coupling-device part and at least one second form-fitting element, which corresponds in particular to the at least one first form-fitting element, is arranged or formed on the second coupling-device part, wherein the at least one first form-fitting element, which is arranged or formed on the first coupling-device part, and the at least one second form-fitting element, which is arranged or formed on the second coupling-device part, are designed to interact in a form-fitting manner to form an axial connection between the first coupling-device part and the second coupling-device part, wherein the form-fitting interaction of respective first and second form-fitting elements (7, 8) always ensures an axial connection of respective coupling-device parts (5, 6), wherein corresponding form-fitting elements (7, 8) are designed not just to interact in a form-fitting manner to form an axial connection between the or a first coupling-device part and the second coupling-device part, but are also designed to interact to form a guide for the first coupling-device part and the second coupling-device part, the components of the guide being moveable relative to one another in the radial direction, wherein at least one first guide element is arranged or formed on the first coupling-device part and at least one second guide element, which corresponds in particular to the at least one first guide element, is arranged or formed on the second coupling-device part, wherein the at least one first guide element, which is arranged or formed on the first coupling-device part, and the at least one second guide element, which is arranged or formed on the second coupling-device part, are designed to interact to form a guide for the first coupling-device part and the second coupling-device part, the components of the guide being movable relative to one another in the radial direction, wherein corresponding radial movements of the first coupling-device part relative to the second coupling-device part, or vice versa, make it possible for the internal diameter of the first coupling-device part or of the second coupling-device part to be altered in a specific manner. a hollow-cylindrical coupling device having a first hollow-cylindrical coupling-device part, which can be or is assigned to a first pipe element, and having a second hollow-cylindrical coupling-device part, which can be or is assigned to a second pipe element, which can be or is connected axially to the first pipe element, wherein at least one first form-fitting element is arranged or formed on the first coupling-device part and at least one second form-fitting element, which corresponds in particular to the at least one first form-fitting element, is arranged or formed on the second coupling-device part, wherein the at least one first form-fitting element, which is arranged or formed on the first coupling-device part, and the at least one second form-fitting element, which is arranged or formed on the second coupling-device part, are designed to interact in a form-fitting manner to form an axial connection between the first coupling-device part and the second coupling-device part, wherein the form-fitting interaction of respective first and second form-fitting elements (7, 8) always ensures an axial connection of respective coupling-device parts (5, 6), wherein corresponding form-fitting elements (7, 8) are designed not just to interact in a form-fitting manner to form an axial connection between the or a first coupling-device part and the second coupling-device part, but are also designed to interact to form a guide for the first coupling-device part and the second coupling-device part, the components of the guide being moveable relative to one another in the radial direction, wherein at least one first guide element is arranged or formed on the first coupling-device part and at least one second guide element, which corresponds in particular to the at least one first guide element, is arranged or formed on the second coupling-device part, wherein the at least one first guide element, which is arranged or formed on the first coupling-device part, and the at least one second guide element, which is arranged or formed on the second coupling-device part, are designed to interact to form a guide for the first coupling-device part and the second coupling-device part, the components of the guide being movable relative to one another in the radial direction, wherein corresponding radial movements of the first coupling-device part relative to the second coupling-device part, or vice versa, make it possible for the internal diameter of the first coupling-device part or of the second coupling-device part to be altered in a specific manner.