j5 create JUA310 - USB 3.0 VGA Display Adapter - Manual (Page 39)

USB DISPLAY ADAPTER
USER MANUAL
38
Mirror mode-Duplicate
This feature allows the same contents of the on-board screen to be
displayed to the screen of the USB 3.0 Display Adapter
You can select “Duplicate these displays” and click “Apply”
Note:
The resolution for the secondary and primary displays must be the same
when using Mirror Mode (This may be lower than the preferred resolution
for the display). Only 2 displays can be mirrored at the same time.
Windows 7 OS may have other limitations.