Somewhat akin to a rather large ratchet. Usually made of Iron(thus the name), they are used primarily to unscrew bolts when changing tires and in films where women drive in pickup trucks and pickup hitchhikers.

Back in the day they were a straight rod of iron that flattened to a point at one end, and slanted out and opened to a hex nut shape at the other. These little beauties were good not only for loosening the nuts and working the jack, but also made handy attitude adjusters when the need arose. Or so I'm told.

Today's tire irons tend to be four-spoked jobs that are more flexible tire removers, but just are of no use for whackin' someone out.