Levers can be used to exert a large force over a small distance at one end by exerting only a small force(effort) over a greater distance at the other.
ClassificationSimple machine
Componentsfulcrum or pivot, load and effort
Examplessee-saw, bottle opener, etc.

A lever (/ˈlvər/ or US: /ˈlɛvər/) is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into three types. Also, leverage is mechanical advantage gained in a system. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage. The ratio of the output force to the input force is the mechanical advantage of the lever. As such, the lever is a mechanical advantage device, trading off force against movement.