: Projects on sites like the Internet Archive often host these split 7z files to preserve complete runs of rare magazines that are otherwise out of print.

When a digital collection—such as high-resolution scans of hundreds of magazine issues—is too large to upload or download as a single file, it is split into numbered parts (e.g., .001 , .002 , .003 , .004 ).

This specific file is most commonly associated with a large archive of the magazine, a vintage Japanese publication focused on radio, electronics, and animation. Understanding Split Archive Files

I can help you look for specific indices or contents if you're having trouble extracting the file.

: You can use the 7-Zip Official Tool or WinRAR to open the first file ( .001 ), which will automatically pull data from part .004 to rebuild the original folder. What is "Radio Mirror Ani"?