Original adjustable This wrench comes in multiple options of sizes 8, 10, 12 and 14 inch the fixed jaw can withstand bending stress far better than can the movable jaw, Because the latter is supported only by the flat surfaces on either alongside the guide slot, Not the full thickness of the tool. The tool is therefore usually angled to facilitate the movable jaw s area of contact is closer to the main part of the tool, Which means less bending stress. Still, One should avoid applying excessive force on tight bolts, Since doing so can pry open the mounting of the movable jaw causing the wrench to no longer possess the ability to be snugged to or mar, Bolt heads loosen too, Bolt heads easily. Occasionally the jaws of the tool can break.