This panel enables you to control which URL's are grabbed (i.e. downloaded), crawled (i.e. have their content scanned for URL's) or saved to disk by specifying restrictions (filters) on the URL's properties - like its filename.
For example suppose you only want to save all files which are HTML files. Then you can choose "Save a resource only if the..." from the popup button, and enter "text/html" into the "MIME type contains" text field.
Note that when entering values which correspond to parts of a URL, like its name, you must make sure it is "URL encoded." To determine a URL encoding you can use your webrowser.
It is important to note that filters are not applied to the starting URL.
All filters specified must be TRUE for the file to be processed.