Files with the .Z01 extension contain the first part of a compressed split archive, usually created with WinZip software. Subsequent files have extension names .Z02, .Z03, and so on, are compressed using the same method as the entire ZIP archive.

Unpacking an archive that has been divided into parts is possible only if you have all of its complete elements. Splitting is used, for example, when one needs to send a large archive as a limited size e-mail attachment.