The Army Weapons Department issued specifications for a design for the Panther's replacement in the spring of 1943.2 It was to have as many parts be interchangeable between the Panther and the King Tiger.2
It was to have a smaller turret that would have better protection, but also would take less time and resources to build.2 It was to be able to take the 7.5 cm KwK 42 L/70 or the 8.8 cm KwK 43 L/71 guns.2 This turret was called schmal Turm.4
MAN and Henschel started on a new design in April 1943. Two prototype hulls were made and one was equipped with PzKpfw V Ausf G turrets for trials. This resides at the Patton Museum for Armor, in Fort Knox, Kentucky.
Daimler-Benz produced 8 prototype hulls in 1945. Had steel rimmed wheels. New hull ball mount that used MP/StG 44 assault rifle. Turret front was 120 mm, sides/rear 60 mm, and roof 30 mm. Infrared telescope and searchlight were mounted and a new rear gun port for a MP/StG 44. Permanent aerial base and fittings were installed so that it could become a command tank in the field quickly. MG 42 became coaxial gun.