A jab saw is for cutting holes in sheet rock. Just mark you holes, then "jab" the pointed end of this tool through the sheet rock and start sawing on the line. You can turn radius corners or pull out the saw and jab it in again to turn the corner. Includes safety scabbard.
By the way, "professional grade" mostly means that the blade is sturdy enough that it won't bend and buckle when pushing the tool in. This is the most common failure of jab saws...they rarely wear out.