The Sturmgeschütz (StuG) series included some of the most widely deployed German armored vehicles of World War II. Still, even its vehicles were modified. In 1942, a request for a self-propelled assault gun with stronger firepower was fulfilled by mounting a 15cm sIG 33 gun to a StuG chassis. The resulting vehicle was dubbed the Sturminfanteriegeschütze 33B, or StuIG 33b. The twenty-four units built in 1942 were the only units ever built.