465 Technical terms
Restraint systems
Seat belts, child restraints, lower an-
chors and tethers for children (LATCH). 
As independent systems, their protec-
tive functions complement one anoth-
er.
Rim
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page 337)
Roll bars
Occupant protection system which 
consists of tubular steel, integrated in 
the rear head restraints. The roll bars 
are lowered into the car body during 
normal driving conditions and raised 
automatically in an accident or in a crit-
ical driving situation.RON
(R
esearch O
ctane N
umber)
The Research Octane Number for gaso-
line as determined by a standardized 
method. It is an indication of a gaso-
line's ability to resist undesired detona-
tion (knocking). The average of both 
the ->MON (Motor Octane Number) 
and RON (Research Octane Number) is 
posted at the pump, also known as 
ANTI-KNOCK INDEX.
Shift lock
When the vehicle is parked, this lock 
prevents the gear selector lever from 
being inadvertently moved out of 
positionP without SmartKey turned 
and brake pedal depressed.
Sidewall
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page 337)Soft top
Soft top roof that can be opened by 
pulling and closed by pressing a switch 
and stored in the soft top compartment 
in the trunk area. 
Speedshift (CLK 500, CLK 55 AMG)
Steering wheel gearshift control. You 
can change the gears yourself with the 
steering wheel gearshift buttons. 
SRS
(S
upplemental R
estraint S
ystem)
Air bags, air bag control unit (with 
crash sensor), emergency tensioning 
device. Though independent systems, 
they are closely interfaced to provide 
effective occupant protection.