To keep other water departments from being able to access your water, towns spec'd their own unique nut designs for operating their hydrants and removing nozzle caps...many,many different size pentagon nuts [and nozzle threads as well]. Hydrant wrenches have a threaded handle on one of the five faces. With this adjustment, it will fit many pent. nuts. This is a rather bulky tool, however, with limited applications. Would be interesting to know the OP's application.
'04 Journey 39W