Wrenches are designed to hold and tighten nuts, bolts, screws and various other threaded parts. However, the type of task you are about to perform specifies your choice of the wrench.
Like all other tools, wrenches are available in a variety of shapes and sizes. They could be open-ended, box, combination, adjustable or striking wrenches. Regardless of their type or size, the purpose of the wrench is to tighten the fasteners or other threaded parts precisely and safely.