Lla 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. Its ordnance inventory designation was Sd.Kfz. 161.
The Panzer IV was the most widely manufactured German tank of the Second World War, with some 8,500 built. The Panzer IV chassis was used as the base for many other fighting vehicles, including the Sturmgeschütz IV assault gun, Jagdpanzer IV tank destroyer, the Wirbelwind self-propelled anti-aircraft gun, and the Brummbär self-propelled gun.
Source: Panzer IV sur Wikipedia