.Z04 File Extension
What is a Z04 file?
The fourth part of a split archive created with select file compression utilities, such as Corel WinZip and WinRAR; uses the same compression as a standard .ZIP file, but must be decompressed with related split archives.
The Z04 file is preceded by files with .Z01, .Z02, and .Z03 extensions. It may also be followed by other files if the split archive contains more than four parts. All files must be available in order for the archive to be decompressed successfully.