Files with the .ZAB extension contain audio data – an audio recording of a literary publication read out lout by a lector, compressed into a ZIP file. The compression makes it easier to move and send large files, as it limits the space they occupy.

An audiobook saved in the ZAB format allows the user to listen to the book after they unpack it using ZIP decompression software, such as WinZip. For some programs, one must change the extension from .ZAB to .ZIP to enable decompression, as the software does not recognize files of the former type.