A 12-point box-end wrench is shown in Figure A-9 Auto Technician says this tool used to loosen bolts that are very tight B spaces where it can be?

A 12-point box-end wrench is used to loosen very tight bolts because its 12 points provide a greater contact area with the bolt head compared to a 6-point wrench. This distributes the force more evenly, reducing the chance of rounding off the bolt head, especially under high torque. The increased number of points also allows for a quicker approach angle - you don't have to be as perfectly aligned to engage the wrench.

As for where it can be used, the location depends on accessibility. Since it's a box-end wrench (meaning it encloses the nut/bolt head), it's best suited for situations where:

* There's enough clearance to fully engage the wrench onto the bolt head. It won't work if the wrench can't fully surround the bolt.

* The bolt head is not obstructed. Pipes, other components, or limited space can prevent its use.

* The bolt head is accessible. The wrench needs a straight path to the bolt. This makes it unsuitable for recessed or hard-to-reach areas.

In short, a 12-point box-end wrench is valuable where strength and a forgiving approach angle are needed, but only where physical access allows it to fully grip the bolt.