A monkey wrench is a tool that has been used since the 19th century to loosen or tighten nuts and bolts. The adjustable wrench was originally invented and patented by Charles Moncky, which is why it is also known as the monkey wrench. The 1900 version was one of the first of its kind and was made of steel. The Monkey Wrench has an adjustable jaw that allows the size of the wrench to be matched to the size of the bolt or nut. The jaw is adjusted by turning a wheel on the end of the wrench. The Monkey Wrench is a versatile tool used in everything from automotive and aircraft maintenance to household repairs. Although the Monkey Wrench has been in use for over a hundred years, it has evolved over time. Modern versions are often made from lighter materials like aluminum or plastic and have more ergonomic handles for a better grip. There are also electric versions of the wrench that allow bolts and nuts to be loosened and tightened more quickly.