I just received my DM42 from Switzerland! Made by SwissMicros, this unit has an SN of 835. If you are not familiar with this RPN calculator manufacturer, I would describe in one sentence what they do: take a classic Hewlett-Packard calculator, improve its design, et voilà! The DM42 is an HP-42S equivalent. It runs the free42 software stack. The quality of the hardware is simply remarkable. The build and materials’ quality is impressive. Great job SwissMicros! The display is astonishing (the pictures are hardly representative) and is close to what an e-ink display is. Add a lot of new features, extensibility, and you get very close to the perfect RPN calculator! Note that SwissMicros offers other models, each of them quite innovative. For example, I also own a DM41L. This calculator is an HP-41CX equivalent in the form factor of an HP-15C!