Allen wrench

An Allen wrench, also known as a hex key, is a small, L-shaped tool designed to turn screws or bolts with hexagonal (six-sided) recesses. Its shape provides leverage to easily tighten or loosen fasteners that have hex sockets. Made typically of metal, it comes in various sizes to match different fasteners. Allen wrenches are commonly used in assembling furniture, bicycles, and machinery because their compact size and simple design allow access to tight or recessed spaces efficiently. They offer a straightforward, durable way to secure or release hex screw fastenings.