The United States International Trade Commission, Office of Tariff Affairs and Trade Agreements is responsible for publishing the Harmonized Tariff Schedule of the United States (HTS). The U.S. Customs Service is responsible for administering the tariff and for processing import entries. The HTS provides the applicable tariff rates and statistical categories for all merchandise imported into the United States. It is based on the international Harmonized System, the global classification system that is used to describe most world trade in goods

Reciprocal Tariffs-Trump Executive Order-April 2nd
By the authority vested in me as President by the Constitution and the laws of the United States of America, including the International Emergency Economic