Monkey Wrench

A monkey wrench is a type of smooth-jawed adjustable wrench, a 19th century American refinement of 18th-century English coach wrenches. It was widely used in the 19th and early 20th century. It is of interest as an antique among tool collectors and is still occasionally used in practice. More broadly, a monkey wrench may be a pipe wrench or any other kind of adjustable wrench.