Oh. So they look like a pair of big wire-cutters.
I see the phrase "jaws of life" in the newspapers once in a while, but had no idea.
I'd imagined it something like a big crane but rather than with a hoist, with some sort of mechanism that stretches things apart, and lifts someone or some thing out of a tight spot.
<<doesn't do television, remember, so hasn't seen all.
The Jaws will cut through metal (also fingers, but that is a story for another time*), crush, pull a steering column away from a trapped driver, spread apart a mangled car door from the frame (as in the picture), and lift like a scissors jack. It's a versatile rescue tool.
It's also a heck of a nutcracker on slow days at the fire station!
For really heavy-duty lifting, there are "air bags" which will lift an entire truck.
[youtube=425,350]http://www.youtube.com/watch?v=ATrOkUBvpYY&feature=related[/youtube]
*I have all of my fingers.