While OS X includes built in support for compressed archives, the number of supported formats leaves a great deal to be desired. Rucksack is an advanced archive tool that can be used to open and create archives in a variety of formats including zip, 7zip, rar and Stuffit.
Creating an archive is a simple matter of dragging files onto the Rucksack window before choosing a name and format. Archives can be encrypted and password protected to ensure that sensitive data does not fall into the wrong hands.
The process of decompressing archives is similarly simple, and nothing more than drag and drop is required. The application also makes it possible to convert archives between formats in a couple of easy steps.
If you are using archives as a means of backing up data, you may find that you create files that are too large to fit on media such as recordable CDs. With Rucksack this is not a problem, as large archives can be easily split into a number of different pieces that can be recombined at a later date.