The third stage/type of economic integration is customs union. Member countries of a customs union abolish all the trade restrictions among themselves and implement a common external trade policy in the third countries. Moreover, the customs union member countries act together as a single entity at the negotiation and conclude the trade agreements with the other countries (third countries). The implementation of the common external tariff avoids the possibility of trade deflection or transshipment. Certainly, it is one step further through a deeper integration. Member countries leave their independence in deciding and implementing their own tariff rates.