Thor 316C Copper Replacement Face Size 4 (50Mm)Thor cylindrical copper faces are manufactured from 99. 9% pure extruded electrolytic copper rod. These copper faces when fitted into a malleable iron head prevent damage to expensive machined sub components and assemblies. These Thor copper face heads are ideal where a heavy blow is required in a relatively small striking area. The faces are designed to wear and can be easily replaced. Size: 4. Diameter 50mm (2 in)