The Czech Republic is bound to adopt the euro in the future and to join the eurozone once it has satisfied the euro convergence criteria by the Treaty of Accession since it joined the European Union (EU) in 2004. The Czech Republic is therefore a candidate for the enlargement of the eurozone and it uses the Czech koruna as its currency, regulated by the Czech National Bank, a member of the European System of Central Banks, and does not participate in European Exchange Rate Mechanism II (ERM II).