The Mercedes-Benz S-Class, formerly known as Sonderklasse (German for "special class"), is a series of luxury flagship vehicles produced by the German automaker Mercedes-Benz, a division of German company Daimler AG. The S-Class designation for top-of-the-line Mercedes-Benz models was officially introduced in 1972, and has remained in use ever since. The S-Class has debuted many of the company's latest innovations, including drivetrain technologies, interior features, and safety systems (such as the first seatbelt pretensioners). The S-Class has ranked as the world's best-selling luxury sedan, and its latest generation, premiered in 2013. In automotive terms, Sonderklasse refers to "a specially outfitted car." Although used colloquially for decades, following its official application in 1972, six generations of officially named S-Klasse sedans have been produced. Previous two-door coupe models of the S-Class were known as SEC and later S-Coupe. In 1998 the S-Class coupe was spun off in a separate line as the CL-Class, however as of June 2014, it has been re-designated as the S-Class Coupe for the 2015 model year, doing away with the CL-Class. In 2016, the S-Class Cabriolet, internally named A217, was introduced with three variants: the S 550 Cabriolet, the Mercedes-AMG S 63 Cabriolet with 4Matic, and the Mercedes-AMG S 65 Cabriolet. The Mercedes-Maybach S 650 Cabriolet, based on the S 65 Cabriolet, was announced in 2016.