In 1943, Auto-Union was ordered to design fully tracked reconnaissance vehicle for the needs of the Eastern Front. The vehicle was to carry 6 to 8 soldiers acting as a personnel carrier and was not to engage enemy vehicles. In early 1944, Auto-Union produced full scale mockup along with two prototypes. The fighting compartment was open at the top. The crew consisted of driver (on the left) and MG42 gunner (on the right). The fighting compartment layout was similar to the Sd.Kfz.251 personnel carrier. The vehicle was powered by 180-200hp Maybach HL 50Z engine. Armor protection ranged from 14.5mm (sides and rear) to 30mm (front). The chassis combined newly designed components (e.g. overlapping steel-rimmed wheels) along with those of PzKpfw IV (e.g. tracks). Both prototypes were tested at Berka in the Summer of 1944 and numerous mechanical problems were encountered. In September of 1944, Auto-Union was ordered to end work on the design and BMM was ordered to continue work by adaptating Jagdpanzer 38(t) Hetzer chassis. One of two Auto-Union prototypes designated as Gepanzerter Mannschaftransportwagen Katzchen (Kitten) was captured by the US Army in early 1945. Two prototypes based on PzKpfw 38(t) nA (neuer Art) were ordered. BMM's design was similar to that of Auto-Union, but featured some modifications (e.g. two MGs instead of one, engine on the right instead of left, improved armor protection - 50mm front, etc). Two type of engines were considered and tested, 220hp Tatra 103 and 280hp Praga NR. The BMM's design had better performance than the Auto-Union one e.g. maximum road speed of 64km/h and maximum cross-country speed of 40km/h with range of 600km. Production of BMM's design designated as Vollkettenaufklarer 38(t) Katzchen (Kitten) was planned but never took place and two prototypes were probably destroyed late in the war.