StreamStats operates through your Web browser window. You do not need to download anything to use it. Currently, two versions are available; version 3 and beta version 4. Version 3 should be used any official purposes, such as for permitting decisions. Beta version 4 is being made available on a trial basis to obtain user feedback and to provide access to some tools that are not available in version 3. See the StreamStats home page for a description of the differences between the tools that are available between version 3 and beta version 4. The Version 3 User Instructions and the Version 4 User Instructions pages provide detailed instructions on use of the applications and example outputs, which you should read before attempting to use StreamStats. Also, both StreamStats user interfaces contain a Help button near the upper right corner that gives access to the user instructions and additional information.