How to tell dual pane/thermal pane windows on Arctic Fox?

To determine if the window is dual pane:
From inside the camper, with the door open, place your finger on the outside rear window with one hand. With the other inside hand place the opposing finger against the finger seen on the outside. You will see a space with a gap between the two fingers if it is dual pane.
If not dual pane, you will see the thickness of one sheet of glass between the two fingers.