The design of a wrench extender—AKA knuckle duster, AKA torque amplifier, AKA power bar, AKA snap-on wrench extender—is similar across manufacturers. It’s a rounded or rectangular bar with two opposite lugs on one end, spaced a few inches apart. The lugs fit and lock the wrench. Thus, you can add leverage and increase torque.
However, like any other tool, not all extender designs are efficient. For instance, you can’t use most extenders on a box end, or they won’t fit several wrench sizes.
Instead of bombarding you with several models, we want to focus on the best one: the Mueller Kueps wrench extender.