Tools are general-purpose appliances; props are special-purpose appliances. Just like the poker cards used by the magician show, it is specially designed, so the equipment used by the magician is called a prop, not a tool.
The switch action of precision machining in China is to use props as much as possible without using tools. Props can improve the efficiency of switching, and shorten the switching time. The most important point is to try to reduce the types of items in order to reduce the time for finding, picking, and dropping.