Rename it can literally save you hours by allowing you to change multiple files extension in one process. To use it, simply select the folder that contains the files and enter the current extension as well as the new extension. The program will list the number of files to be renamed and process them with the click of a button. Rename It also offers a single file mode, that allows you to select the individual files to be renamed, rather than mass-renaming based on a wildcard extension.