my41cx 1.1 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The application belongs to Productivity Tools. The actual developer of this free software for Mac is Miroslav Perovic.
From the developer:
my41cx is an advanced programmable and expandable RPN calculator for OS X Yosemite. It is a functional equivalent to the world famous HP-41C/CV/CX calculator. Four module ports provide access to HP-41 expansion pacs. The tool offers support for .MOD files.
You may want to check out more Mac applications, such as Unit Converter, DVC Calculator or CalcME, which might be similar to my41cx.