What type of power tool is commonly used for tightening and loosening fasteners?

An impact wrench is specifically designed to efficiently tighten and loosen fasteners, especially in applications that require high torque. It delivers sudden, powerful bursts of torque to the fastener, which makes it ideal for tasks such as changing tires on vehicles or assembling heavy machinery where a significant amount of force is needed. The mechanism of an impact wrench combines rotational motion with powerful impacts, allowing it to drive or remove fasteners quickly and easily without requiring excessive manual effort.

In contrast, a screwdriver is typically limited to manual tightening and loosening tasks and cannot match the power and efficiency of an impact wrench for larger fasteners. A drill is mainly used for creating holes or driving small screws, and while it can be used for fastening, it does not have the same torque capabilities as an impact wrench. A rotary tool is versatile and often used for sanding, grinding, and cutting tasks but is not primarily designed for tightening or loosening fasteners. Thus, the impact wrench is the most effective tool among the options provided for this specific purpose.