An Allen wrench, also known as a hex key or hex wrench, is a simple tool used to drive bolts and screws with hexagonal heads. It is typically made of hardened steel and has a hexagonal cross-section. Allen wrenches are available in a variety of sizes to fit different bolt and screw heads.
The Allen wrench is named after its inventor, William Allen, who patented the design in 1869. Allen wrenches are widely used in a variety of industries, including automotive, construction, and manufacturing.
