While I was at a local thrift shop I stumbled upon a Casio fx-190 Electronic Rule/Calculator.
I have been reading the manual and it seems to to do quite a bit more than I expected.
Information online is scarce and I cannot really find much about it. I have two conflicting years of introduction.
Is this a really rare calculator? It is very heavy and has a mostly metal construction. While the box/manual are in rough shape, the calculator is fully working and very clean.
If anyone has some information on year/rarity/etc. that would be great. And maybe about the measuring part, I cannot fully understand why you would need the 2nd display.