RAR File Open Knife - Free Opener is a program that can decompress RAR archives.
It does not create RAR archives, it just decompress them. And it cannot decompress any other type or archives. The installer will automatically register RAR File Open Knife as the default application to open files with the RAR extension. Then, you will launch this program if you double-click on a RAR file. Also, when right-clicking on a RAR archive, the context menu will show the "Extract!" command, that will launch this program. You can also drag a file into the program´s window, or open the program and then browse to find the archive you want to decompress.
RAR File Open Knife can open encrypted files, by using a default password or a list of passwords that can be configured into the program´s interface. You can configure where to save the extracted files, if you want to create a separate folder for each extracted archive and if it should open the destination folder after extraction. The program can be run in fifty languages.