Haha, are you asking about CMC? Look carefully, is there a capital "C" wrapped around MC?

CMC is the symbol of "China Metrology Certification License" and the English abbreviation of "China Metrology Certification", which means China's Manufacturing Measuring Instrument License. Enterprises that have obtained a license to manufacture measuring instruments can mark the CMC mark on the measuring instruments they produce. This mark indicates that the measuring instrument manufacturing enterprise has the ability to produce measuring instruments, and the accuracy and reliability of the measuring instruments produced meet legal requirements.