Customs Union

A Customs Union is a form of economic integration between countries in which member countries agree to eliminate tariffs, quotas, and other trade barriers on goods traded between them, while maintaining a common external tariff on imports from non-member countries. In other words, member countries of a Customs Union form a single customs territory with a common trade policy towards the rest of the world. 

Customs Unions are established to promote trade and economic cooperation between member countries, as well as to reduce the administrative burden and costs associated with complying with multiple sets of trade regulations. By eliminating internal trade barriers, member countries can increase trade flows, promote greater efficiency and specialization, and increase competition within the region.