What does it do? File Renamer works very simple. You enter the file extension you want added to your files and then you click a button. Now you simply choose the folder in which the files are. Now File Renamer simply adds the extension to the names of all the selected files. What can i use it for? If you e.g. make web pages, image work etc. on your Mac, then you might not give your files the proper file extensions because the Mac can identify the files by their creator code. This is not the case on Windows machines. Windows machines idintify the files by their file extension (e.g. eps). If you have made a lot of files on your Mac and want to e.g. send them to a PC friend or in work situations, then you have to give all the files the extensions to make sure that the PC user can open the files. Normally you would add this extension to the files names manually. Not anymore. File Renamer does this for you. Just type the extension and select the files and you're done.