Folders Size Shell Extension - Version 2.20 A free shell extension for Windows 95 and Windows NT 4.0 or above. It adds a new page to the Properties dialog box for folders and drives. This new page allows you to see the folders and sub folders sizes (in a hierarchical tree). To access to the option (units, sort, save as text, etc.) a contextual menu is provided. This freeware is a graphical equivalent to the UNIX "du" command.