216 is a galvanized trivalent chromium color passivation process. Its anti-corrosion performance is extremely high, and the neutral salt spray test can reach more than 144 hours. It has excellent high temperature resistance, up to 200°C, a long service life of the solution, and low cost. The operation is simple, just soak in 216 to form a layer of bright and uniform colored film. The color is bright and various, such as yellow, blue, purple, red, etc. It is suitable for cyanide zinc plating, alkaline zinc plating, and acid zinc plating.