The first mass produced Panther type D was not equipped with a machine gun but after the experience of close battle. A 7.92mm MG 34 was added to the Panther's right front hull armament beginning with its type A. The special feature of the Panther was the left and right driving mechanism. This created an interchangeability of movements, using the torsion bar system. By 1944, the Panther was further improved from Type A to Type G with a change in its side shape.