Wrench is a common installation and dismantlement tool, which is used lever principle twist bolt, screws, nuts and other threads tightly hold bolts or nut opening or sleeve hole firmware hand tools. Wrenches are usually made of Constructional Steel of carbon or alloy materials.

Wrench usually has an opening or sleeve hole for clamping bolts or nuts at one or both ends of the handle. When using, the bolt or nut can be screwed by exerting external force on the handle along the direction of thread rotation.