This option is available for the USC-2 and the USC-3.

It enables the second XY2-100 scan head interface of the card.
Both scan heads execute the same job and typically share one laser.

Each head can have its own optical settings including the correction file.

Using an additional data splitting board it is even possible to control three 2D scan heads. More information about this special mode is available here.

Please find more information about option Head2 here.