Cuprum 4.1.2 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. The actual developer of this Mac application is Remco Poelstra. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. Cuprum for Mac lies within Productivity Tools, more precisely Office Tools.
From the developer:
Cuprum is a simple Gerber viewer for the OS X platform. At the current state, it’s a simple multilayer viewer with basic printing support. There are two versions: Full and Community Edition. The (paid) Full version contains fully functional versions of the latest and greatest features. The Community version contains limited versions of some features.
You may want to check out more Mac applications, such as Cuprum Community Edition, which might be similar to Cuprum.