The unit of weight has a long history. In ancient times, all countries had their own units of measurement. In ancient China, the unit of weight was Jun, that is, 30 Jin was one Jun, 10 Gui was one Baht, 24 Baht was one Liang, and 16 Jin was two. At present, China has specific units of measurement, such as kilograms, tons and pounds in the United States and Britain.