Which of the following statements best describes a socket wrench?

The statement that a socket wrench fits over the head of a nut or bolt for better leverage accurately describes its primary function. Socket wrenches are designed to fit snugly around the fastener's head, typically either a nut or a bolt, which allows the user to apply greater torque without slipping. This design enhances the grip and allows for more efficient application of force, making it easier to tighten or loosen fasteners compared to standard wrenches.

The socket itself is typically attached to a ratchet mechanism, which enables the user to turn the wrench back and forth without removing it from the fastener, further contributing to ease of use and functionality. This design is particularly beneficial in tight spaces where traditional wrenches may be difficult to maneuver.

The other options do not accurately define the purpose or functionality of a socket wrench, focusing instead on different tool characteristics or types that do not apply to the socket wrench specifically.