7-Zip is a free open source utility that was developed in 1999 by Igor Pavlov and since that time has been constantly updated. This Windows file compression program is available in a wide variety of languages and includes a number of different features.
7-Zip is notable for its high compression ratio. It is capable of shrinking files by creating 7z archives that are considerably smaller than its commercial rivals' zip files, though the compression process might take longer. Unfortunately the list of supported compression formats doesn't look impressive: besides 7z and Zip, the only popular format the utility can convert is Tar. The number of supported extraction formats is a way bigger and includes ZIP, CAB, RAR, ARJ, GZIP, LZH, CHM, BZIP2, TAR, CPIO, RPM, DEB, etc.
Apart from that, 7zip can offer an encryption feature which will help users to protect their archives content with a password.
The program doesn't use many resources and can be switched to background mode. The interface of the program can be considered minimal and thus is rather easy-to-use.
7-Zip won't impress you with any specific features that will mark it out from software of the same kind. Still it has all the necessary functions you'll need in an archive manager and it has them extremely well made. Besides it has one big advantage over its rivals: it is absolutely free.