The SL-Class is comprised of three models: the SL550, the SL63 AMG and the SL65 AMG. The SL550 is powered by a 382-hp 5.5-liter V8 engine, mated to a seven-speed automatic transmission, while the SL63 AMG boasts a hand-built 518-hp 6.3-liter V8, as well as a seven-speed MCT (multi-clutch technology) transmission not found in any other Mercedes model. The SL65's larger 6.0-liter bi-turbo V12 generates an immense 604 horsepower, and is paired with a five-speed automatic transmission. The SL63 AMG and SL65 AMG are outfitted with aluminum shift paddles, while all models feature aggressive AMG body styling and an adaptive suspension with Active Body Control (ABC). Standard equipment on every SL-Class model includes a power retractable hardtop, heated leather seats, dual-zone automatic climate control, Bluetooth wireless connectivity, satellite radio, 6-disc CD/DVD changer and a voice-activated hard drive-based navigation system with four gigabytes of internal media storage. Safety features include four-wheel anti-lock disc brakes, an electronic stability program (ESP) with traction control, Bi-Xenon headlamps with Active Curve Illumination and an automatically deployable rollover bar, as well as front, side and driver knee airbags and the Mercedes mbrace system. After a one-year hiatus, the Mercedes-Benz SL-Class returns for the 2011 model year with minimal changes. All models are now equipped with HD radio and an advanced tire pressure monitoring system. Additionally, the SL600 model has been dropped from the lineup.