These two prototypes underwent trials in late 1944. The complete vehicle was long, wide and high. Weighing 188 metric tons, the Maus's main armament was the Krupp-designed 128 mm KwK 44 L/55 gun, based on the 12.8 cm Pak 44 anti-tank field artillery piece also used in the casemate-type "Jagdtiger" tank destroyer, with a coaxial 75 mm KwK 44 L/36.5 gun. The 128 mm gun was powerful enough to destroy all Allied armored fighting vehicles then in service, some at ranges exceeding .