I finally bit the bullet and bought an HP-16C "Programmer's Calculator". It was made in the US in 1982.

I am fully aware there are 100 different ways I could get the same functionality on my computer or phone, but my fingers are wired for #RPN and the feel of an #HP keyboard.

I am experiencing a lot of #NerdHappiness.

https://www.hpmuseum.org/hp16.htm