'Ponton' is the German word for Pontoon and refers to the way that the wings were now incorporated into the bodywork instead of having separate front and rear wheels as most pre-war cars did. The first 'Ponton' was the Mercedes-Benz 180 (W120) which went on sale in 1953. The 180 was powered by a 1,767cc version of the pre-war M136 sidevalve engine. In 1957 the 180 was upgraded (as 180a) with the 1897cc sohc M121 engine, which was also given to the 190 (W121) model in 1956. The M121 was used in the 190SL sports car, but the 190 did not get twin carbs, and the 180 was even lower tuned. Both the 180 and 190 could be ordered with 4-cylinder diesel engines and the diesel car was popular as a taxi. The 180b and 190b were produced from 1959-61 with modifications which included a better subframe. Six cylinder 'Pontons' were launched in 1954 with the 170mm longer 220a (W180) fitted with the M180 2195cc inline six engine. The 220S replaced the 220 in 1956 with a more powerful engine and other improvements. At the same time the 219 was launched with a detuned version of the 2195cc engine fitted into a shorter W105 body. A two-door cabriolet 220 was also launched in 1956, designed by Friedrich Geiger. Fuel-injected 220SE models were available from 1958 to 1960 (as the W128).