I'm pretty old but I've never seen one of those...wtf is it?
At 75 I am probably a bit older than most on the forum , things have changed a lot and not always for the better.
They were the original mechanical calculator , the old 1880,s one pictured is cranked by hand to turn a complicated system of cogs , gears and pawls , slower in use than an electronic model but just as accurate.
Noisy in use and needs an hour a week to clean and oil the innards.
The shelf on the left is to take a manual typewriter to record results.
Postwar they were powered by an electric motor and were cheaper , an early model cost as much as a car to buy and comptometrist was a recognised profession.
You can see them and sliderules still in use on early pictures from NASA and Los Alamos , more powerful and reliable than early computers.
I used one in the 60,s in aerospace design till they were scrapped , never thought to save one then but wish I had.
If you can find a manual portable model at a boot fair snap it up , antique of the future and an amazing example of quality engineering , most were thrown away when electronic calculators became available so getting rare and expensive in working order.
Much more fun than an 80k enigma machine and it still does a useful job.