This vehicle came into production on 2 Apr 43. Considered to be the best in Italian Self-Propelled Guns (SPG) it was armed with a 105 mm 25 Caliber howitzer on a M43 chassis. This chassis was the same as the M 15-42, but widened 7.9 feet (2.4 meters). The hull superstructure had 70mm of armor protection and the rest of the vehicles armor ranging from 15 mm to 50 mm.
A total of 494 were ordered, however, only half were built by the time of the armistice signing. The Germans utilized these vehicles after the Italian armistice of 8 Sep 43, and used them effectively against the Allies in Italy.