It is used for extruded aluminum bar in product finer.it has error (0.01MM), technical features: after high temperature graphitization, it has established special high purity stone product system with high density (≤30ppm), high density (1.85g/cm3), high strength and isotrope, etc. It can be used for a long time under 1700 ℃ in vacuum or non-oxidized atmosphere. Can be produced according to the drawing.