[b]Allen wrenches[/b] (also known as "hex keys") are small L-shaped hexagonal-prismatic steel bars that used as a [[wrench]] to loosen or tighten fasteners like [[bolt (hardware)|]]s or [[screw]]s  that have heads with internal hexagonal recesses (sockets).

h4. See also

* [[Impact wrench]]
* [[Socket wrench]]
* [[tools]]

h4. External links

* "Wikipedia: Hex key":[https://en.wikipedia.org/wiki/Hex_key]
allen wrench