Um, none. There are no free trade zones in the United States. The U.S. program has the same acronym, but a different name. It also offers deferral of Customs duties and fees, but works quite differently. See ‘What is a Foreign-Trade Zone?’

Free Trade Zones are economic development projects set up in countries around the world to promote employment and international trade. They are typically established by governments in locations targeted for increased job growth. Often these free trade zones (also known as FTZs) will offer limited assembly, packaging, and shipping services to companies wishing to take advantage of the preferential duty […]