That pentagon might open a fire hydrant and the spanner next to it could be used on post type hose couplings but I don't think that this tool would be carried on a firetruck. I've never seen one in my 40 years in the fire service, and I am a longtime member of several antique fire apparatus clubs.
There was a discussion awhile back on a very similar wrench. Everyone agreed that the pentagon and pin couplings could be used on a hydrant and hose couplings but there was no agreement on what the larger end could be for.
My contention is that it is most likely used in the irrigation industry as that larger six sided opening would probably be used on a portable pump of some type.
Nothing in the fire service, that I know of, has a hex that big.
