It could be well used in a UPS box with my address on it =)
It looks like other autotransformers I've seen so as stevez said it's likely not isolated. Could be used to dim standard incandescent lightning. Keep in mind most auto transformers I've seen provide 0 to 110% of the input voltage so you can over voltage stuff if it's turned all the way up.
Try feeding it power from a 12 V AC wallwart if you want one and put a meter on the output to see if it still works, it looks to be in very nice shape.
My prefered use would be adding an issolation transformer some power diodes and beefy caps to turn it into a 0-120 volt DC power supply.