Game Invasion: Blue Collar Mechanic

It has been ten years since the system came into existence, and no one has seen upgradable talents. Lu Shu's "rusty hand" is the first. Green level, extraction speed 0.1Kg/second, mana consumption 10 points per second, single element, grade limit 10%. On the surface it looks like waste, but the upgrade conditions column has a question mark, like a locked door. He started with an iron pot. In five seconds, the mental power drops by 50, and a pure iron ball appears in the palm of the hand. Silvery white, warm, and purer than the scraps from the workshop in the previous life. Lu Shu suddenly realized: This is not talent, but a production line. A production line that can be run by just one person. What if the grade restrictions are removed after upgrading? What if the speed is raised to 1kg/second? What if... He could sift uranium out of the soil? This idea is crazy. But the system gave him the words "upgradeable", which made him crazy.