B1 Free Archiver is an all-in-one tool that can archive and unarchive files in a number of formats, all within a secondary interface on your device. Because B1 is designed as a universal tool, it handles all of the major formats, including RAR, ZIP, 7Z, and a proprietary B1 format to ensure you can unzip any file on your device. Considering the limitations of the Mac archive tool, this is a welcome set of features, especially in a tool that's free.
After installation, which involves moving the program to the Applications folder, you can open B1 to browse files on your computer. You'll get a full secondary Finder window where you can select and zip folders and files into any format you want. By default, B1 becomes your unzip option, as well, so when you download a new compressed file, it will open it for you, either in the browser or immediately unzipping into the same folder. The real value of B1 comes in the number of options it offers, though. With drag-and-drop support, archive within archive functionality, and password encryption you can take your efforts to the next level with this app.
If you are interested in an archiving app that is free, handles multiple formats, and allows you to protect your files much better than the default tools on your Mac allow, then B1 Free Archiver is a great download.