This style of window has been around since the early 2000s, tried and tested with very efficient concealed drain tubes hidden under the glass, window locks in closed position only, now also available with the opening section towards the front of the van.
Old Faithful with Integral Fly Screens
Ideal for sleeping with the windows open in Campervans
Basically as above but incorporates a sliding Fly Screen which can slide independently of the window, they are also easily removable on most models.
This model has a different type of catch which is not visible from outside for a cleaner look, it simply flicks over when closed to lock
The sliding pane sits flush with the main window when closed but cantilevers inward and slides along behind the main window to open, locking fully open, closed or at several mid-way points.
The original design was the rear opening type but more and more customers asked for the opening at the front to resemble the genuine Volkswagen windows.