The cap (1) has a connector (2) for injecting medical liquid into a container, and another connector (3) for removing the liquid from the container. The connectors comprise outwardly pointing connection parts (4, 5) with conical recesses for accommodating taper shafts of devices e.g. needle-less nozzle (28) and transfer hose, in a sealing manner, respectively. The connection parts are designed as a luer-lock-female connector. The connectors are arranged in a cover area (19) of the cap, where the cover area is surrounded by an edge area (20) that attaches the cap on the container.