Which wrench is designed to grip and turn a pipe or pipe-shaped object, tightening when turned in one direction?

The pipe wrench is specifically designed to grip and turn pipes or pipe-shaped objects. Its unique design features serrated teeth that bite into the surface of the pipe, providing a strong grip. The handle allows for leverage when turning the wrench, which is especially useful when needing to tighten or loosen pipes securely. When the wrench is turned in one direction, the jaws tighten around the pipe, ensuring that it doesn't slip and can effectively apply the necessary torque to the pipe.

While the monkey wrench also has adjustable jaws, it lacks the specialized grip and mechanism that the pipe wrench provides for handling round objects like pipes. A reamer, on the other hand, is used for enlarging holes rather than gripping and turning, and the torque wrench is designed for measuring the amount of torque being applied to a fastener, not for gripping pipes. Therefore, the pipe wrench is the correct tool for the task described.