An element configured to be mounted at an end of a pipe suited to circulation of a fluid to extend the pipe. The element includes a hollow profiled body including a peripheral surface and a protective covering at least partially covering the peripheral surface. The element further includes a sensor of guided waves type, control electronics for the guided wave sensor, and an electric cable configured to connect the control electronics to corresponding electronics of the pipe. The electric cable and the guided wave sensor are fixed to the peripheral surface of the body under at least part of the protective covering.