There are different types of gray cardboard. Its thickness is different in each of its types, which depends on its application. This thick paper also has different brands. Cardboard made in Korea includes Horse, Dragon, Tiger and Panda brands. China produces Linman brand products. Iran's production includes first-grade Etrak brand for export and second-grade Etrak brand. Its high quality and first grade is used for color prints, which has a higher resolution and its color is transparent. The second-grade type and its weaker quality is more useful for monochrome and two-color prints, which is a little darker in color.