suitable medium such as air or water for example wherein the filling level or the pressure of the medium respectively is monitorable by way of suitable devices in fig1 initially a simplified exemplary embodiment is illustrated in which exemplary embodiment only a single tube 4 which is correspondingly disposed in or on the sealing strip 2 such that said single tube 4 indicates the foreseeable service requirement is provided to this end the tube 4 is sensibly disposed in that region of the wear volume 3 that is closest to the suction box that is to say at the bottom as seen in relation to the wear direction here no observation of the temporal profile of the wear of the sealing strip would be possible rather early maintenance is to be rapidly planned instead this variant impresses with simplicity low susceptibility to errors and low manufacturing and maintenance complexity in fig2 a sealing strip 2 in which three tubes 4 1 4 2 4 3 are provided is illustrated said three tubes are embedded in the material of the sealing strip 2 which for example may take place directly in the manufacture of the sealing strip 2 or only later on the tubes 4 1 4 2 4 3 may also be disposed in a groove in the sealing strip 2 and fixed so as to be capable of.