i-tec USB-C Dual Display MST Manuel D'utilisation page 11

Mirror mode: This mode can only be used if supported by the Mac.
Click on Gather Windows: using this option you can choose the settings of the corresponding
monitor – Scaled (offers available resolutions), Rotation (Standard, 90°, 180° and 270°) and
Refresh rate (if offered).
Depending on your monitor there are these options for settings:
Option number 1: