The mirror roller is mainly used in dyeing and pringting industry, plastic cement industry and paper making industry, etc. The max hardness of the product is up to HRC55-58. After lathing and grinding and hard Chrome Plating, the surface hardness can up to HRC62. After fine processing ,pre-polishing and precise polishing, the max. smoothness can be up to Ra0.01 umm(Level14), the thermal deformation is no more than 0.01 mm. Please contact me for details.