Abstract: A pressure container suitable for gases, liquids, paste-like materials or similar products comprises two chambers sealed against each other. One of the chambers is constituted by a flexible bag connected to a valve plate common to both chambers. The valve plate is provided with an extension tube extending into the interior of the container. A neck portion of the flexible bag is glued or welded to the extension tube. The outer contour of the extension tube comprises radially extending projections which are bounded by two outer faces each, and which, at their inner ends, merge tangentially into the circle-shaped contour of said first extension tube means and converge into a sharp edge at their outer ends. In this way, a reliable sealing of the two chambers against each other can be achieved.