The Panzer I was a light tank produced by Nazi Germany in the 1930s. Its name is short for Panzerkampfwagen I, abbreviated as Pz.Kpfw. I. The tank's official German ordnance inventory designation was Sd.Kfz. 101. Many of the problems in the Ausf. A were corrected with the introduction of the Ausf. B. The air-cooled engine was replaced by a water-cooled, six-cylinder Maybach NL 38 TR, developing 100 metric horsepower, and the gearbox was changed to a more reliable model. The larger engine required the extension of the vehicle's chassis by 40 cm and this allowed the improvement of the tank's suspension, adding another bogie wheel and raising the tensioner. The tank's weight increased by 0.4 tons. Production of the Ausf. B began in August 1936 and finished in the summer of 1937 after 399 had been built in two series .
