David Butleradded October 4, 2019

Here we are. I have been hunting for this one for awhile. The Gould's Pumpulator was a customized version of the Business Analyst-I. It was made specially for Gould's Pumps, which is a pump company that is still around.
The ROM chip has been replaced with a custom set with calculations specifically for working with pumps. I believe that this was only available to workers at Gould's Pumps, and it was not sold to the public. This differs from other customized calculators like the ones produced for Western Auto or True Value Hardware. As such, this calculator is quite rare.
I included some images of a PDF of the manual. It should do a better job than I could with explaining the various functions.