What's so compelling about the Knipex Pliers Wrench? They are a cross between an adjustable wrench and a pair of pliers. The smooth (non-marring) jaws can be adjusted quickly and grip very tightly on the nut or bolt being turned. The adjustment is made by pressing a spring-loaded button and sliding the lower jaw up and down.
This product has been around for years but I was not aware of it until recently because Knipex is not widely distributed in this country. I bought mine (the 7-inch model) from Chad's Toolbox. I have since found them at Amazon.
Knipex tools are made in Germany. They're not cheap, but if you have the chance to handle them you'll see why they cost more than others; the fit and finish is excellent and in the case of these pliers, the design is unique.