no need. Tianjin Ostrich Ink Co., Ltd. (formerly Tianjin Tianjin Ink Factory), its "ostrich" brand products are divided into five categories and more than 1 varieties of colors. The products are sold in 27 provinces, municipalities and autonomous regions in China, and need not be diluted when used. Ostrich brand products have been rated as "Tianjin Famous Brand Products", "National and Tianjin Customer Satisfied Products", "China Consumer Trustworthy Products" for many times, and have won awards such as "China Famous Brand Products in Pen Making Industry" and "China Ink King", and the ostrich trademark has been recognized as "China Well-known Trademark" by the State Administration for Industry and Commerce.