I use one called 48sx, however, I've only ever used +-*/. Clicky physical buttons are much better of course. An accountant I worked with years ago had one with

I use one called 48sx, however, I've only ever used +-*/. Clicky physical buttons are much better of course. An accountant I worked with years ago had one with a printer, which meant she had a paper record and could verify that the entries were correct.