As the German invasion of Poland in September 1939 came to an end, it was decided to scale up production of the Panzer IV, which was adopted for general use on 27 September 1939 as the Sonderkraftfahrzeug 161 (Sd.Kfz. 161).
Cando a invasión alemá de Polonia en setembro de 1939 rematou, decidiuse aumentar a produción do Panzer IV, que foi adoptado para un uso xeral o 27 de setembro como o Sonderkraftfahrzeug 161 (Sd.Kfz.