The two anti tank guns of the Vallo Alpino next to each other. On the right is the 57 mm gun model 1887. This was a former naval gun designed to defense large vessel against fast torpedo boats. This made them well suited for the anti tank role. However by 1935 they were slowly replaced by the more powerful 47 mm gun which was the standard infantry gun of the Italian army. Quite often this gun had no armoured plate while the 57 mm was often protected by a 2100 kg heavy steal plate.