Use 7-Zip, WinRAR, or PeaZip to unarchive .7-zip archive and also you can use them to create Compressed file from a multi-volume archive (.001, .002 etc.)
Convert 7z compressed archive to Compressed file from a multi-volume archive (part 1).
We have found 3 software records in our database eligible for .7-zip to .001 file format conversion.
Microsoft Windows software - convert 7-zip to 001 on Windows
One of the oldest and most popular shareware file archiver and data compression utility
Convert from 7-zip file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned 7-zip to 001. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Popular open source file archiver with a high compression ratio
A free open source archive utility