Initially designed for infantry support, the StuG III based on the Panzer III chasis became probably the most numerous of Germany's armoured fighting vehicles in WWII. The StuG III was armed with the 7.5cm StuK40 L/43 or L/48. The Sturhhaubitze 42 was based on the StuG III and introduced to provide heavier support for the 7.5cm StuK on the StuG III. It was armed with a 10.5cm StuH42 L/28. StuH42 were provided on the basis of 9 vehicles to each StuG Brigade to provide heavier firepower.