A foreign-trade zone is an isolated policed area adjacent to a port of entry (as a seaport or airport) where foreign goods may be unloaded for immediate transshipment or stored, repacked, sorted, mixed, or otherwise manipulated without being subject to import duties. These zones are domestic U.S. sites that are considered outside U.S. Customs territory and are available for activities that might otherwise be carried on overseas for customs reasons. For export operations, the zones provide accelerated export status for purposes of excise tax rebates. There is no issue of drawback because duties are not collected when the goods are in the FTZ. For import and reexport activities, no customs duties, federal excise taxes, or state or local ad valorem taxes are charged on foreign goods moved into FTZs unless and until the goods or products made from them are moved into U.S. Customs territory. Thus, FTZs can be profitable for operations involving foreign dutiable materials and components being assembled or produced here for reexport. Also, no quota restrictions ordinarily apply to export activity.