Wrenches are hand tools used for tightening or loosening fasteners like bolts and nuts. Wrenches come in various types, including adjustable, pipe, and torque wrenches, each designed for specific applications. These tools are available in different sizes and materials, such as chrome-plated steel and alloy steel, offering durability and strength for various tasks. Shopping for wrenches online provides a broad selection, ensuring you can find the right wrench for your mechanical or plumbing projects.