A science teacher at the coffee shop tried to explain how two different metals (in this case: aluminum and steel) can fuse together by a chemical (and somewhat electrical) reaction. Similar to how a hot water heater aluminum anode will accept the corrosion of the interior of the tank. I know "galvanic" was a word he used . . . anyway - this thing is like a solid block of multiple metals.
Photo Above: "The guy said it ran last year."
I researched, and they only made about 5701937 WL models.