This part is 25mm wide and has a hole for a keystone jack for use with RJ45/USB/HDMI/etc jacks.  For whichever side of the center skirt panel you wish to place this part, drop down to the next lower size skirt end.  So if you are using a 350mm printer, use the 300mm skirt on that side.  Those skirts are 25mm shorter on each side and will allow the exact amount of room needed for this part.