The four common tools used for turning nuts, screws and bolts are the Socket wrench, Nut Driver, Adjustable wrench and Open End wrench.
The popular Adjustable is undoubtedly reached for before the others, but ironically disappoints the user many times when clearances turn out to be tighter than anticipated.
Selecting the proper size of Open End wrench, especially for the smaller fasteners that could be Metric or SAE, becomes a trial and error game.
By removing any jaw adjustment method from the head of the wrench and locating it in the handle, the new head profile is sized down to become comparable with that of Open End wrenches.
A considerable amount of users time and frustration will be saved by this design.