Sturmgeschütz (or StuG) meaning "assault gun" was a series of armored vehicles used by both the German Wehrmacht and the Waffen-SS armored formations during the Second World War that primarily consisted of the StuG III and StuG IV. The more common of the two, the StuG III, was built on the chassis of the proven Panzer III. The StuG III was initially designated "StuG" but with the creation of the StuG IV it was re-designated the "StuG III" to distinguish the two.