Abstract: The invention relates to a suction or blowing cylinder of a machine which is used to produce and/or shape paper, cardboard, tissue or another fibrous material (2). Said cylinder comprises a rotatable, perforated cylinder covering (1) and at least one pressure area (4) which is connected to a lower pressure source or a high pressure source and is sealed in relation to the cylinder covering (1) with the aid of at least one sealing element (5, 6). The invention is characterised in that the sealing element (5, 6) is embodied in a flat-shaped manner and is arranged in the vicinity of the inner wall of the cylinder covering (1).