Traceless repair is actually micro-sheet metal. In fact, the principle is very simple, that is, based on optics and mechanics, using the lever principle, the pits with different depths are slowly restored from the inside. The repair effect depends on the technical level of the master. If the technology is strong, you can't see any problems from the front. For individuals, the advantage is that seamless repair does not need to destroy the original car paint. Hope to adopt, thank you!