Schmalturm was based on the tank that was developed in what time frame?
Schmalturm:  B Panther II medium tank, Panther A and G medium tank, Panzer IV Ausf. Panzer IV: The "Panzerkampfwagen" IV (PzKpfw IV), commonly known as the Panzer IV, was a German medium tank developed in the late 1930s and used extensively during the Second World War.
late 1930s