Refractory shapes, not of metal; refractory workpieces, not of metal, including compound workpieces, namely, refractory bricks, refractory blocks; refractory bricks, not of metal; refractory building and construction materials not of metal, namely, refractory concrete, refractory cement, for use in continuous casting plants; refractory shapes not of metal, namely, refractory monoblock stoppers, for use in continuous casting plants; refractory shapes, namely, refractory monoblock stoppers not ...