Unlike a customs union (the third s

Unlike a customs union (the third stage of economic integration), members of a free-trade area do not have a common external tariff, which means they have different quotas and customs, as well as other policies with respect to non-members. To avoid tariff evasion (through re-exportation) the countries use the system of certification of origin most commonly called rules of origin, where there is a requirement for the minimum extent of local material inputs and local transformations adding value to the goods. Only goods that meet these minimum requirements are entitled to the special treatment envisioned by the free trade area provisions.