This is the 18" model of a patented adjustable wrench by Craft. I am unsure as to it's exact purpose (and so is everyone else who has one that I have found on the internet and there has only been a few), but I assume it was intended to be employed where space was at a minimum due to the very narrow mouth. ANY HELP IN THIS RESPECT WOULD BE APPRECIATED. The 18" model is especially hard to locate - this one is in fine condition. Thanks foe looking - if you have a few minutes, I have many other tools listed in my Ebay store, including  THE 12" MODEL OF THIS WRENCH. (LS5 - 0422)