An open-end wrench is a hand tool used for gripping and turning nuts and bolts. It features two parallel jaws that can fit over the fastener, allowing for quick adjustments without needing to remove the tool. Open-end wrenches come in various sizes to accommodate different fastener dimensions. These wrenches are commonly made from steel for durability and are often part of a larger set that includes other types of wrenches, such as box-end wrenches and socket wrenches. They are essential tools in automotive repair, construction, and general maintenance tasks.