Hex, Torx KeysHex keys and Torx keys are tools that are used to turn bolts and screws that have a hexagonal or star-shaped socket in the head. Hex keys, also known as Allen keys, are L-shaped or T-shaped tools that have a hexagonal shape on the end that fits into the socket of the bolt or screw. Torx keys are similar, but have a star-shaped end that fits into a corresponding socket on the bolt or screw. These tools are commonly used in automotive and industrial applications, where bolts and screws with these socket types are commonly used. Hex keys and Torx keys are available in a range of sizes to fit different socket sizes, and are often sold as sets that include multiple sizes.