Embodiments of a device for protecting and sealing the opening of a container. This device is a one-piece made plug for a flask or container, comprising at least one passing channel, and at least one structural flow regulator barrier, allowing the passing of solid elements. The structural regulator barrier comprises at least a gate to regulate the passing and connection between the inside space and the outside space of the container in a unidirectional and/or bidirectional way. An embodiment includes a method and a mold for manufacturing such a device.
