Hans Nibel designed a shorter, open-top version of the Mercedes-Benz Mannheim and introduced it in 1931 at the Berlin Motor Show.
In 1929, after Dr. Ferdinand Porsche left Daimler-Benz AG, Dr. Hans Nibel assumed its role of chief designer. He worked on the existing model 350 designed by his former colleague and improved the car in every possible way. Moreover, it added two convertible versions in 1931, with a long or a short wheelbase, respectively. They also shared the lowered chassis. The shortest version was named Mannheim 370 S, with the internal code WS 10.
Wit a shape that resembled the SSK, the WS10 featured a flat and vertical radiator grille at the front and a chromed bar that supported the big headlights. In front of it, the carmaker installed a chromed bumper-mounted directly on the chassis endings. Behind them, the curved, long wheel fenders continued their lines on the side steps to the rear wheel fenders. Just like its predecessor, the W05 350, it featured a curved engine lid and a flat, but with a shorter windshield. At the back, Mercedes-Benz installed a big trunk, very useful on long journeys.
The leather-clad interior matched the car's status as a personal luxury roadster. Its wooden dashboard featured an instrument panel with four dials. Mercedes-Benz added two glove-compartments on each side for the driver and passenger.
Under the hood, the W10 started with the same 3.5-liter engine as its predecessor, the 350 W05. By 1931, when the convertible WS appeared, Mercedes-Benz already developed an upgraded, 3.7-liter unit. It was an inline-six that provided 75 hp, five more than the 1929 Mannheim.