cuff depending on the region to be covered the cover device can therefore also be formed solely by the inner cap 8 in this exemplary embodiment the cover element i e the membrane 20 has a water vapor permeability of less than 0 05 m a tensile stress resistance of more than 300 n 50 mm and a tear resistance of more than 300 n it can be used in a range between u2212 50 u00b0 and 120 u00b0 and has a water tightness of more than 2 m water column furthermore it is uv resistant for more than three years in the embodiment shown the cap with pipe is merely shown as a mechanical sealing element securing of the cap takes place only by way of the sealing lips 16 which are not shown pressed in and turned and prevent the cap from being pulled out at least in part in an embodiment according to fig4 the cover device according to the invention is furthermore provided with a security device 22 that is disposed on the inside 18 of the pipe wall at least with a structure borne sound sensor not shown in any detail here the security device 22 has electronics that can pass a signal on to a corresponding base station by way of a transmitter disposed in the membrane for example for this purpose the signal generated by a structure borne sound sensor can first be filtered within the security device according to amplitude frequency and length an energy storage unit preferably a rechargeable one serves as the power supply for the security device this unit can keep energy available for a sufficiently long period of time over the transport periods.