A box wrench, also known as a box-end wrench, is a hand tool used for tightening or loosening nuts and bolts. It features a closed loop, or "box," at one end that fits over the fastener, providing a secure grip. This design allows for better torque application compared to open-end wrenches, making it ideal for working in tight spaces. Box wrenches come in various sizes and are often made from durable materials like chrome vanadium steel for strength and longevity. They can be found in both standard and metric sizes, catering to different types of fasteners commonly used in automotive and mechanical applications.