R.I.P. Scout26
That was most like a Curta mechanical calculator. They were QUITE advanced, and have something of a cult following now. They also tend to bring quite high prices -- asking prices on various internet sites are well north of $1K depending on the model. I have my Father's Curta. Not sure where my Grandfather's Curta got to. Neat rundown on how they came to be... the originator was a "guest" of the Nazis during WW II.https://newatlas.com/curta-death-camp-calculator/45506/
Your post got me digging, and I found most of it. Looks like one of my girls took it apart a few years back.