For ease of use, the car comes with a universal electronic-mechanical key, which is both a control panel for the alarm system and a central lock. The purpose of the buttons and key components is shown in the figure 7.
Figure 7
1. Control LED
2. Lock button
3. Rear door and tailgate/boot release button
4. Mechanical key lock button
5. Mechanical key
6. Unlock button
Original source of information (www.mercedesman.ru)