 Production began in spring 1943, with the 75 mm L/34 gun (the same as on the Carro Armato P 40) on the chassis of the M15/42 tank.Some sixty were built before the Italian armistice in September 1943.While derived from the earlier Semovente, it differed somewhat from it; instead of two conjoined plates each thick, the frontal armour was made of a single thick plate and the casemate was modified to fit the longer gun.