Investment casting we called here is American style silicon gel process(with green wax and better sand) with very good smooth surface, tight tolerance, suitable for small part making widely used for stainless steel. It's different with Russian style investment casting actually called soluble glass process(with white wax and rough sand)with relative rough surface, bigger tolerance, suitable for large part making more than 1.00KGS especially for carbon steel, alloy steel, sometimes also for ductile iron and grey iron.