More accurately: "Designed by Apple in California. Components from Taiwan, South Korea, Japan, USA and China. Assembled in China."
If you count the value added in China, only $8.50 of the cost of iPhone comes from China. Chinese import components to assemble iPhone.
Slapping $160 tariff to iPhone assembled in China is indirect tariff to the US allies in the region and even to the US itself. Foxconn can move their iPhone assembly to Vietnam but it takes time.
http://theconversation.com/we-estimate-china-only-makes-8-46...