Some products that they started to import and export (world trade) were largely related to mechanical and technical stuff. They started to copy the materials manufactured in the outside world (as they called it) and tried to make the same thing in the least possible prices. At first the things did not go as planned by the supervisors; but then gradually, the experts started learning from their mistakes and everything they made was about the same quality as its original Sibling!
China ball bearings and mechanical parts for vehicles were also part of the same positive-conspiracy!
The people benefited from all parts of the world; not only the Chinese but the foreigners who were deprived of lesser priced goods of the same quality were also blessed with some china ball bearings and suspension parts thanks to the trade permissions.