A Customs Union is an agreement between two or more countries to eliminate tariffs and other trade barriers on goods traded among them. This arrangement allows for the free movement of goods, making it easier and cheaper for businesses to trade across borders. Countries in a customs union also adopt a common external tariff on goods imported from outside the union, ensuring that all member countries apply the same duties. One well-known example of a customs union is the European Union (EU), which facilitates trade among its member states while maintaining a unified trade policy with non-member countries. By participating in a customs union, countries can enhance economic cooperation and strengthen their collective bargaining power in international trade negotiations.