Abstract: The invention concerns an improvement of sleeves such as sleeves for gramophone records. The sleeves consist of a front and a back panel connected at one edge by a connecting strip, which is in the blank arranged between the two panels, and two other connecting strips extending from one panel and glued to edge zones of the other panel by means of gluing flaps. Gluing flaps and edge zones which are to be glued together in overlapping position are reduced in their thickness so that the seam is as thick as the material of the back panel. Reduction in thickness is achieved preferably by milling off a layer from the cardboard material of the gluing flaps from their outer surfaces as well as of the edge zones at their inner surfaces. The sleeves have panels of equal thickness so that the gramophone records are supported all around their edges and in their middle parts without causing bending when stacked.