An end cap which is prepared for being fastened, especially attached, to an especially pipe socket-type connecting port of a cartridge-shaped receptacle and in a mounted state serves for sealing the connecting port, including a top surface portion, a shell surface portion being connected, especially perpendicularly and cylindrically, to the top surface portion, and a flange portion connected to the shell surface portion, the flange portion including and/or forming a sealing portion, by which the end cap can be fixed and sealed to the cartridge-shaped receptacle, and a predetermined breaking/tearing portion, at which the end cap tears and/or breaks in a predefined manner when the end cap is removed from the cartridge-shaped receptacle.
