Abstract: A stopper rod comprises an elongate body having an inlet at an upper first end and an outlet at a lower second end. The second end of the body defining a nose for insertion into a tundish outlet. A continuous axial bore extends through the body from the inlet in the first end to the outlet in the second end. A restrictor having an inlet, an outlet and a passageway therebetween, is positioned in the axial bore such that the inlet of the restrictor is closer to the first end than the second end. A gas supply conduit is arranged to supply gas into the axial bore above the inlet of the restrictor.