7-zip is a open source compression tool whose whole code is under GNU LGPL license except the unRAR code which is under mixed license of GNU LGPL + unRAR restrictions. For more info about the license check out [license](http://www.7-zip.org/license.txt).
This means that you can use 7-zip without registering or paying for it.
**The main features of 7-zip are:**
> It has high compression ratio in 7z format with LZMA compression. You can know more about 7z format here.
> For packing it supports 7z, ZIP, GZIP, BZIP2 & TAR formats. For unpacking it supports 7z, ZIP, GZIP, BZIP2, TAR, ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z formats. > It provides 2-10% better compression ratio than PKZip and WinZip for ZIP and GZIP formats.
> For 7z and ZIP formats it has strong AES-256 encryption.
> Self extracting capability for 7z format.
> Integration with Windows Shell.
> Powerful File Manager.
> Powerful command line version.
> Plug-in for FAR Manager.
> Localization for 74 languages.
> Windows: GUI working with 7, Vista, XP, 2008, 2003, 2000, NT, ME, 98.
> Linux/Unix: Command line version for both Debian based and RPM based distros.
On [7-Zip’s Source Forge Page](http://sourceforge.net/projects/sevenzip/) you can find a forum, bug reports,
and feature request systems.
You can download the 7z from [here](http://www.7-zip.org/download.html).
For more info you can ask us or go to [official site](http://www.7-zip.org/)