7-Zip is one of the best free archivers. This free software has a high rate of compression and extraction; users may add password for an archive. The application works with the following formats 7z, XZ, BZIP2, GZIP, TAR, ZIP, WIM, CAB, CHM, CPIO, DEB, DMG, HFS, ISO , LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z. Moreover, it is able to unpack ARJ. Freeware is a good alternative to comercial WinRAR.