Top 4 is an application generally classified as a file compression and decompression program. Development and support for this software has long been discontinued, but this is the main application that is associated with TO4 files (archives with the .to4 extension). The Top 4 file compression and decompression program can allow users to select files and folders that will be included in an archive which can then be created with this application, and the data compression technology used by this software when saving these archives is the TO4 file format. The content of TO4 archives can also be edited or modified with the Top 4 software, which means users can remove or add new files to these TO4 archives by accessing the corresponding functions that are implemented into the Top 4 file compression and decompression tool.