European Union Customs Union
The European Union Customs Union (EUCU), formally known as the Community Customs Union, is a customs union which consists of all the member states of the European Union (EU), Monaco, and the British Overseas Territory of Akrotiri and Dhekelia. Some detached territories of EU states do not participate in the customs union, usually as a result of their geographic separation.
Source: Wikipedia — European Union Customs Union (CC BY-SA 4.0)