Toward the end of World War II, the German tank industry came up with the concept known as the E-Series. One of the program's vehicles was the E 65. The tank used Horstmann-type suspension from the Steyr company, and the drive wheels were at the rear of the hull. The main difference from other vehicles in the series was the idea of mounting two guns on a single turret. The tank was assumed to be able to fire either salvo or cyclic rounds at an increased rate. However, the E 65 never went further than the general concept stage.