CBR and CBZ to PDF is an easy-to-use free tool which converts one or more CBR or CBZ files to PDF.
The conversion process is straightforward. Click Browse, choose a CBR or CBZ (or a RAR/ ZIP containing images), click Convert; a PDF is created in a few seconds in the same folder as the source file; clicking Open PDF Location opens an Explorer window at that folder, and you can view or do anything else with it as required.
Figuring out how to process multiple files takes just a little longer. You can't select several files in the Browse dialog, and dragging and dropping them onto the program doesn't work, either. Instead you must select Mode > Advanced, then click Add Folder, choose a folder containing your source CBR/ CBZs to import them all, finally deselecting any you don't need. Not ideal, but once you've figured it out there's no problem.
You don't get any detailed control over the exported PDFs, no options to directly set resolution, metadata or anything else. But a Settings dialog does allow you to define page size and margins, and there's also a handy option to merge all your processed CBR/ CBZs into a single PDF.
Selecting multiple files is a little more complicated than it should be, but overall CBR and CBZ to PDF is a quick and easy converter which works just as you'd expect.