7-Zip is a really powerful manager for compressed files, it includes all the basic functions and it supports the most usual compression formats (7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM y DEB) housed in an interface fully integrated in the windows style.
The main features of 7-Zip:
- High compression ratio in 7z format with LZMA and LZMA2 compression
- Supported formats:
- Packing / unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM
- Unpacking only: AR, ARJ, CAB, CHM, CPIO, CramFS, DMG, EXT, FAT, GPT, HFS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RPM, SquashFS, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR and Z.
- For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
- Strong AES-256 encryption in 7z and ZIP formats
- Self-extracting capability for 7z format
- Integration with Windows Shell
- Powerful File Manager
- Powerful command line version
- Plugin for FAR Manager
- Localizations for 87 languages

The most interesting feature of this utility is its compression power which is better than any other application, for example, for Zip and gzip files, the compression is 2-10% better than other compressors.
7-zip is a very interesting choice if you want a free compressor.