The buttons of national police uniforms are mostly copper material. China’s people’s police uniforms also use copper metal buttons. The uniform copper buttons are popular in 1658. That year, the Holland government set up a group of 8 local security groups in the capital in 1693, the United States in Washington and some large cities have established similar organizations, which is the first police in the world.
With the established national police organization, the clothing designers create new styles to design uniforms with black nail and copper metal buttons, which results in a strong color contrast. This scientific design, so that the police in maintaining social order is both majestic and easy to distinguish between other industries. Later, this practice is gradually accepted by the governments to follow the design for police suits .