In the context of international trade, customs duty plays a crucial role in protecting each country's residents, employment conditions, and local companies. The duty is calculated based on the custom value of goods, which includes item cost, shipping cost, and insurance cost. Moreover, non-tariff barriers such as quotas, embargoes, and export subsidies can also impact international trade. Additionally, C-TPAT (Customs Trade Partnership Against Terrorism) is a voluntary partnership that aims to enhance security at the border by providing protection to private companies' supply chains from terrorism.