This is a flexible printed circuit board (FPC) widely used in the consumer electronics industry (such as smartphones and smartwatches). With a green cover film as the main body, its circuit line width and spacing can reach 0.1mm/0.1mm, and the substrate thickness is only 0.05mm. It also has super bendable characteristics— tested professionally, the bending resistance exceeds 100,000 times. The fine circuits are arranged in order and matched with high-precision connectors, which can flexibly achieve circuit connection and signal transmission in a limited space; for example, the signal transmission between a smartphone screen and the main board often relies on such FPCs, providing key support for the lightweight and flexible design of electronic devices.