I have found this overlay on a calculator I bought last week . The calculator came without any modules, so no way for me to know what the module does, or what is in memory (it was sold as "for parts" but I managed to return it to life - this is one of the pleasures of our hobby!) Any help will be welcomed. It would be good if it is one of the moudles included in the HP41CL memory!!
I am also considering printing and selling overlays for different modules. Would any of you be interested in any of them