cs-41 6.4 for Mac was free to download from our software library. Cs-41 for Mac is included in Productivity Tools. The actual developer of this Mac application is AD&A Multimedia.
From the developer:
cs-41 RPN Calculator is a professional calculator for Mac. The cs-41 app contains near all the built-in functions of the original HP-41C (including sounds) and the ability to save and restore ilimited programs in "module" files, so you can modify routines, start new ones, erase the memory, quit and reopen the app without worry - the saved modules will remain intact.
You may want to check out more software for Mac, such as pearCalc, Googol or Universal Currency Converter, which might be similar to cs-41.