The appropriate government agency responsible for monitoring and assessing duties on imported products in virtually all countries requires a COO to determine what duty or tariff, if any, should be assessed on the product or products being imported. The U.S. has trade agreements with many foreign countries, and under the terms of many of these agreements, American products receive lower tariff rates or are not subject to a tariff. The foreign customs office verifies whether a product qualifies for preferential duty rates based on the information on the Certificate of Origin that accompanies the documentation associated with the shipment. Also, some countries have banned certain products from countries that have been caught dumping. The COO helps prove that the product is allowed into that particular country.