2005 Mercedes CLK-Class Owner's Manual - Page 461

Technical terms REST (Residual engine heat utilization) Feature that uses the engine heat stored in the coolant to heat the vehicle interior for a short time after the engine has been turned off. Restraint systems Seat belts, child restraints, lower anchors and tethers for children (LATCH). As independent systems, their protective functions complement one another. RON (Research Octane Number) The Research Octane Number for gasoline as determined by a standardized method. It is an indication of a gasoline's ability to resist undesired detonation (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 position P without SmartKey turned and brake pedal depressed. Speedshift (CLK 500*, CLK 55 AMG) Steering wheel gearshift control. You can change the gears yourself with the steering wheel gearshift buttons. SRS (Supplemental Restraint System) Air bags, air bag control unit (with crash sensor), emergency tensioning device. Though independent systems, they are closely interfaced to provide effective occupant protection. 459