http://www.nytimes.com/2016/12/29/technology/iphone-china-apple-stores.html?smid=tw-nytimesworld&smtyp=cur&_r=0  “For an iPhone headed for the China market, customs officials use an electronic system to virtually stamp the goods as “exports” and then restamp them as “imports.” In Zhengzhou, the process happens in the same customs facility just outside the factory.

Once the products are declared an import, customs can collect a 17 percent value-added tax, a kind of national tax, based on the import price. Afterward, the goods are approved for transport around China.”