7-ZIP Open Source Alternative To WinZip

7-Zip is a file archiver for Windows with a high compression ratio. The program supports 7z, ZIP, RAR, CAB, GZIP, BZIP2, and TAR formats. Compression ratio in the new 7z format is 30-50% better than ratio in ZIP format. It also compresses to ZIP 2-10% better than PKZip and WinZip.
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