The Jagdpanzer IV, Sd.Kfz. 162, was a German tank destroyer based on the Panzer IV chassis and built in three main variants. As one of the casemate-style turretless Jagdpanzer (tank destroyer, literally “hunting tank”) designs, it was developed against the wishes of Heinz Guderian, the inspector general of the Panzertruppen, as a replacement for the Sturmgeschütz III (StuG III). Guderian objected against the needless, in his eyes, diversion of resources from Panzer IV tank production, as the Sturmgeschütz III was still more than adequate for its role.
Additional Information: en.wikipedia.org/wiki/Jagdpanzer_IV