The units of machining dimensions are millimeters or inches. The wire you are talking about is one hundredth of a millimeter, which is 0.01 millimeter. 100 wires are 1 millimeter, but wire is a common name in the workshop. In the national standard There is no such unit anywhere in the world. People in the south say it more, while people in the north say that 0.2mm is called 20 channels.