Which tool is a hexagonal-shaped key used to drive hexagonal screws?

• A. Allen Wrench
• B. Needle Nose Pliers
• C. Open End Wrench
• D. Speed Square

Answer: (A)

Hex-shaped keys are made to fit into hexagonal recesses in screws, allowing you to apply torque without the head camming out. The tool known as the Allen wrench, or hex key, matches that hex profile exactly, slipping into hex screws to turn them. You’ll see it often in flat-pack furniture and bicycles where these screws are common. The other tools don’t fit hex sockets: needle-nose pliers grip or maneuver parts, an open-end wrench engages the outside of a hex nut rather than a recessed screw head, and a speed square is used for marking angles and measuring, not driving screws.