All models built in or sold in the are only available in long wheelbase. 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 1996 the S-Class coupe was spun off in a separate line as the, however as of June 2014, it has been re-designated as the 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. Model nomenclature [ ] Chassis Type Debut 'Ponton' 'Ponton' 'Fintail' 'Fintail' 'Stroke 8' S-Class S-Class S-Class S-Class S-Class S-Class In 1993, when the was introduced as C-Class, the traditional naming convention (numbers, plus letters) was reversed, with a leading letter identifying the line (As of late 2017, A, B, C, CLA, CLS, E, G, GLA, GLC, GLE, GLS, S, SL, SLC, V and X are in active use). From then on, the long-wheelbase models (formerly 'SEL') and the regular-length models (formerly 'SE') are both labeled with the prefix of 'S' regardless of length. For example, both 500SE and 500SEL are now labeled as S500/S500L, with fuel injection being standard by now anyway.
The W221 S-Class has been available in four trim levels; the numbers are given in ascending order to denote more upscale models (e.g. S500 (S550 for US)/S600/S63 AMG/S65 AMG etc.). In official Mercedes-Benz publications and on vehicle nameplates, a space between the letter and numbers is customary (e.g. Mercedes-Benz 230S (Belgium) Mercedes Benz (: Heckflosse) is an informal nickname given to Mercedes Benz vehicles notable for the presence of tailfins.