This dialog box lets you define a hot key combination for scanning a mounted, local volume. 

Press the hot key combination you'll use to scan the selected local volume.

The currently selected volume is displayed here. Click the Drive button to change the selected volume.

Click Cancel to clear any changes made during this session and close the dialog box.

Click Select to save the 'For Volume' hot key settings.

Click Drive to change the selected volume.

Click Eject to eject a removable volume from the drive.