Adjustable wrench
A monkey wrench is a heavyweight wrench in which the jaw width is set by a spinning ring fixed under the sliding lower jaw. In 1840, Worcester, Massachusetts knife manufacturer Loring Coes invented it. It was based on the wrench used on English 18th-century coach wheels. Coe patented it in 1841 and the tools were advertised and sold in the United States as "monkey wrenches".