The sports SL cars were already known as early as 1954. The present, fifth generation of the SL model was presented in Frankfurt/Main in 2001. The vehicle features an electrohydraulic mechanism that folds the roof, thanks to which it can transform from an open, 2+2 roadster, into a closed coupe in just 16 seconds. The basic SL 350 version comes with a 3.7-liter 245 hp V6 engine, and the offer also includes an SL 500 version with a 5.0-liter 306 hp V8 unit, and a sports SL55 AMG with a turbocharged 5.4-liter 500 hp engine. The leading SL 600 features a 5.5-liter 500 hp V12 power plant, and its exclusive SL65 variant has been equipped with a 6.0- liter 612 hp V12 engine, which was developed by the AMG. At the beginning of 2005 in Geneva, a prototype of the SL 400 CDI was presented, provided with a 4.0-liter 315 hp V8 diesel engine, which may soon appear on the market as the first top class sports vehicle driven by this type of power plant.