I have a plastic analog (dial) one made by General, which had HO and O scale divisions on it.  From the looks of the letter and number style on it, I wonder if it's German.  Have had it for maybe 15 or 20 years.

It no longer has the O scale divisions on it, because I got confused every time I looked at it to try to take a measurement, so I took a black Sharpie and colored over the O scale numbers.  Crude, but.....

As an engineer, I generally don't want to see numbers that are too accurate, that are more accurate than I can reproduce or that I need.  So wherever the little pointer lands, if it says something is around 6 scale inches, for example, I'm happy with it.  If I was machining something that needed close tolerances, or I needed to stack several things whose tolerances needed to add to a specific value, that would be different, but for my modeling, in general, this is the proper degree of precision for me.

Ron Merrick