A device for determining and/or monitoring a process variable of a medium includes a measuring insert, having a sensor element for sensing the process variable arranged in an end region of the measuring insert, and a dipping body for receiving the measuring insert which at least temporarily and/or partially protrudes into the medium and surrounds the measuring insert at least in a subregion nearest the medium. The device further includes a coupling unit introduced into the dipping body and designed to fill up an inner volume between an inner wall of the dipping body and an outer wall of the measuring insert at least in the subregion in which the sensor element is located as to ensure mechanical coupling between the dipping body and the measuring insert.