You rarely need to use the Advanced Volume Properties dialog box. But, if you want to require that users enter an additional password, beyond their normal login password, when they mount volumes, you can use this dialog to establish that password. On this dialog, you can also limit the number of users that can use a specific volume.
Note: Users are unable to input a password for protected volumes on computers running Mac OSX El Capitan (10.11) and higher. This is an issue in Mac OSX 10.11 and higher.
Note: Volume specific passwords were eliminated in Mac OS X 10.5, but have been re-enabled in Mac OS X 10.6.