Wrenches are a common installation and removal tool. Use the principle of leverage to twist bolts, screws, nuts, and other hand tools that hold the opening or socket firmware of the bolt or nut. The wrench usually has an external force applied to the one end or both ends of the handle to apply an external force to the external force of the handle, so that the bolt or the nut can be screwed or the opening or the sleeve of the nut. When using the external force in the direction of the thread rotation, the bolt or nut can be twisted.