20 mm Flakpanzer auf Panzer I
Is the first attempt to mount an anti-aircraft gun on an armored chassis frame. It was the Flak 38 of 20 mm on the frame of a PzKpfw I Ausf A whose first units entered service in 1941. The system proved useful in battle but the biggest problem was that the chassis of the PzKpfw I dated 1935, was so technical and traction problems in the Russian campaign where roads were not adequate. However, the vehicle was serving on the Russian front until the last of them was lost at Stalingrad in early 1943.