Between the original Unimog and the middle series, Daimler-Benz developed a "light" series. The light series consisted of two separate Unimog series, the 421 and the 403. The 403, which basically is a 406-series with a 3.8-litre four-cylinder engine, has a wheelbase and was later supplemented by the 413-series, which is a four-cylinder-version of the 416-series (long wheelbase () model). The 421 is the successor of the 411-series and has a wheelbase. It is powered by a 2.2-litre passenger car Diesel engine.