Abstract: Described is a supporting hub for an internal slide, which accepts a spooled recording medium, where one side of the supporting hub lies against a ring-shaped supporting surface on the outside of the internal slide, where a reel hub carrying the recording medium or a flange spool can be pushed onto the other cylindrical side of the supporting hub and where the internal slide can be slid into a protective casing. The ring diameter of the supporting surface of the supporting hub lying against the inner side of the internal slide is here the same size or greater than the ring diameter of the supporting surface of the supporting hub lying against the outside of the internal slide. In a preferred embodiment, the supporting hub is in two parts which are detachable from the inside or the outside of the internal slide, and grasp one another.