Panzer III mod. E 

Type: Medium tank
First model of the Panzer III to be mass-produced. It was heavier and better protected than the previous models. It received the definitive configuration of the running, after it had been changed 4 times on the 4 previous models. The engine is more powerful. During its operational life, its armour will be reinforced and it will be rearmed with a 5 cm gun.
The main weapon of the Panzer III was the result of a compromise between the champions of the 3.7 cm gun (same caliber as the infantry antitank gun, easing the logistical problem of the ammunitions) and of the 5 cm gun (more powerful). The 3.7 cm gun was chosen, but the turret was big enough to accomodate a 5 cm gun if necessary.
The model E, with the model F, was the standard Panzer III during the campaign of France. The looses were heavy. Of the 381 tanks engaged, almost a third was lost !
Identification: First model to receive the definitive running gear, with six road-wheels, each suspended with a torsion bar. In contrast to the next models, the gun shield is inside the turret. The vision slit of the pilot differs from the shape on the model F.
Based on: Panzer III

Factory floor of Panzer III model E at the start of the war. Note the six road-wheels (different from the model D) and the shape of the pilot slit (different from the model F).