Original Odhner 24
Run of the mill large Odhner model, without input control register, but with back transfer. I thought at the time I was buying a model 11, but that turned out to be a mistake - the black back-transfer button is missing in this machine, and the metal stud it used to sit on wasn't quite visible in the picture of the machine. The seller did another of those disasterous packing jobs, with the calculator wrapped in a layer or two of bubble wrap and tossed loose in a box, despite being warned about exactly that and having been pointed to my webpage on packing. In any case, considerable damage was done by the time it arrived. Luckily I had parts from a parts machine to repair it. In any case, I ridiculously overpaid, but at least the machine has some interesting history to make up for it. Apparently it came from the Esso company. I tried calling the number on the back to get it serviced and tell them it has been permanently relocated to Belgium, bot no-one picked up the phone.
