Infrared reflective windshield
The infrared reflecting glass prevents the vehicle interior from becoming too hot. It also blocks radio waves up into the gigahertz range.

In order to operate radio-controlled equipment, e.g. toll recording systems, areas 1 on the windshield are permeable to radio waves. In these areas, you can install radio-controlled systems.
These areas can best be seen from outside the vehicle by observing the light reflected off the windshield.
See also:
Safety & Reliability
As of this writing, the Insurance Institute for Highway Safety has not yet
crash-tested the GL-Class. Eight standard airbags include three-row side curtain
airbags and seat-mounted side-impact air ...
Hill start assist
Hill start assist helps you when pulling away
forwards or in reverse on an uphill gradient.
It holds the vehicle for a short time after you
have removed your foot from the brake pedal.
This gi ...
Restoring the factory settings
Press the and
buttons simultaneously for approximately
six seconds until the battery check lamp flashes twice.
...
