Classification of goods: Harmonized System headings and General Rules determine tariff treatment and duty applicability. Classification of goods assigns imported and exported commodities to tariff headings under the Customs Tariff Act by applying the texts of Section and Chapter Notes, Headings, Supplementary Notes and the General Rules for Interpretation in sequence; GIR addresses precedence, incomplete and composite goods, most specific description and essential character, packing and sub heading allocation, while HS Explanatory Notes, trade meaning, technical tests and administrative instruments guide interpretation and ensure uniform tariff treatment.