Arrangement at a plug for sealing liquid- or gas-carrying pipes, comprising several slips (15) arranged peripherally on the plug, so as to allow them to be pushed up along a conical force ring (25) by means of a hydraulic cylinder (5), where the slips (15) are provided with a possibly divided sliding surface (19, 19') and at least one possibly divided sliding surface (20, 23) having an angle that differs from the angle of the sliding surface (19, 19'). The force ring (25) has sliding surfaces (27, 29, 29', 31) that correspond to the sliding surfaces (19, 19', 20, 23) of the slips. The first part of the sliding surfaces (20, 23, 27, 31) has a steep gradient and the second part of the sliding surfaces (21, 21', 29, 29') has a small gradient.