Which tool is used to loosen and tighten multiple or unknown sized hex bolts, adjustable to metric and standard sizes?

• A. Adjustable Wrench
• B. Allen Wrench Set
• C. Fixed Width Wrench Set
• D. Ratchet Set

Answer: (A)

An adjustable wrench is designed to grip hex bolt heads of many different widths by changing the distance between its jaws. You set the jaw gap with a screw, so you can fit both metric and standard bolts within its range and then loosen or tighten them. This versatility means you can tackle unknown sizes with one tool instead of carrying a whole set.

Allen wrenches fit hex sockets inside bolts, not external hex heads, and they come in fixed sizes. A fixed width wrench set can’t adapt to sizes it doesn’t include. A ratchet set relies on swapping sockets, which means you still need the right size socket for each bolt. The adjustable wrench stands out because it adapts to a wide range of sizes with a single tool.