Panzer III Ausf D 431
The Ausf D was the fourth iteration in the series of developing a 15 tons armored vehicle, with an emphasis on improving the suspension system.
The suspension on the Ausf D was further enhanced compared to previous models by angling the leaf-spring assemblies supporting the first and last pairs of road wheels, which helped increase support. Additionally, the Ausf D featured a newly designed sprocket, idler, and transmission. While this was the final model in the series to have 15mm basic armor, it did introduce a new style cupola with 30mm armor and five vision slits. To improve armor protection, the design of the rear deck and hull rear was altered. The louvers on top were substituted with hatches that could be secured in place when opened.
In 1938, the official organization called for three PzKpfw III in a Zug (platoon) in the light tank company (a) of each armored detachment. Thus, each Panzer regiment was only permitted to have six Pz Kpfw III, and each Panzer division, twelve. Following their deployment in Poland, the Ausf D was withdrawn from the Panzer regiments in February 1940. However, they were later utilized by Panzer-Abteilung z.b.V. 40 which fought in Norway in April 1940, extending their front-line service by several months.