Here are some pictures to help clarify things.
In the UK the light projected by the headlight would flick over to the left hand side, however, if you are driving in Europe that would blind on coming traffic. To solve that problem, some W211/S211 headlights have the ability to change the projected light for driving in Europe. Therefore, you do not need to stick a nasty little sticker on your headlight. The light projected becomes flat and will not blind on coming traffic in Europe.
Here is the famous lever, located on right in this picture (currently in the up position for UK roads).

Close up of the lever in the up position.

Close up of the lever in the down position.

In the UK the light projected by the headlight would flick over to the left hand side, however, if you are driving in Europe that would blind on coming traffic. To solve that problem, some W211/S211 headlights have the ability to change the projected light for driving in Europe. Therefore, you do not need to stick a nasty little sticker on your headlight. The light projected becomes flat and will not blind on coming traffic in Europe.
Here is the famous lever, located on right in this picture (currently in the up position for UK roads).

Close up of the lever in the up position.

Close up of the lever in the down position.
