Due to increasingly limited resources, the Germans became masters at reconstituting existing armored vehicles and modifying them to serve new battlefield requirements. This was the case with the late-war Flakpanzerkampfwagen IV "Kugelblitz" ("Ball Lightning") - a self-propelled anti-aircraft vehicle based on the chassis of the famous PzKpfW IV (Panzer 4), the most numerous tank in the German Army arsenal. As the value of the Panzer IV deteriorated during the war due to the arrival of more powerful vehicles, its readily available chassis became the foundation of many-a-late-war project - some serving as anti-aircraft vehicles and others as self-propelled "big gun" carriers.
The Kugelblitz was unique in its design when compared to the earlier German attempts at self-propelled anti-aircraft vehicles for it housed its gunnery crew in a wholly enclosed, fully-traversable armored turret - protected from both battlefield dangers and the elements. The crew numbered five and included a driver in the front-left hull and a bow machine gunner/radio operator at front right. The remaining crew constituted the vehicle commander and two dedicated gunners in the turret. Primary armament was 2 x 30mm MK 103/38 series cannons which were based on the classic MK 103 series aircraft cannon used in many Luftwaffe designs - a weapon already in circulation within the German inventory. The bow machine gun was a 7.92mm MG 34 General Purpose Machine Gun (GPMG) offering some defense from infantry attacks - though its position as a bow-mounted machine gun limited its firing arc. On the whole, the vehicle retained the same general form and function of the Panzer IV medium tank line with its engine at the rear and its hull superstructure sporting vertical walls. The primary difference became its all-new turret structure which was of a low profile design with rounded walls for basic ballistics protection. Overall armor protection of the vehicle reached 80mm (3.1") in thickness and the vehicle weighed in the 25 ton (short) range.
The running gear remained the same as the Panzer IV with its many pairs of road wheels. The drive sprocket was located at front with the track idler at rear and five track return rollers managing the track links over the top of the run. Power was served through a Maybach HL 120 TRM series 12-cylinder gasoline-fueled engine of 296 horsepower output. Road speeds reached 24 mph with an operational range out to 120 miles.
The value of Flakpanzers in German service was priceless for the nation was fighting a wholly defensive war heading into 1945. The Soviet advanced from the East with the Western Allies breaking through from the West and the Italian buffer in the south long gone. With German Luftwaffe assets consistently committed elsewhere it fell to the Army to figure out its own local defense for its advancing convoys. The Allied fighter-bomber had become a major threat to any German land force attempting to move in broad daylight under clear skies.
German officials had hoped that the Kugelblitz would be in serial production by the fall of 1944 but the German war situation was such that the program (like other late-war initiatives) was continually delayed or slowed enough to make little impact in the whole of the war. With that, the vehicle was only realized through five completed pilot (prototype) forms before the end of the war in Europe during May of 1945.