[1][2][3] Similar in shape to a torpedo, it was adapted to carry at low speed two operators, equipped with autonomous underwater breathing apparatus and a limpet mine to be applied covertly to the hull of an enemy ship at mooring.

It was used by the Decima Flottiglia MAS during World War II for sabotage actions against enemy ships, often anchored in heavily defended ports, such as during the 1941 Raid on Alexandria.

The slow-running torpedo was derived from Raffaele Rossetti's Mignatta (Italian for "leech"), used in World War I to sink the Austrian battleship Viribus Unitis.

The first two prototypes of the SLC were tested in October 1935, in the San Bartolomeo torpedo workshops of La Spezia in the presence of Mario Falangola who at the time directed the Submarine Inspectorate.

The carrier was composed of three sections: in the first, rounded in shape to facilitate navigation, the charge (approximately 260 kg of TNT) along with the corresponding detonation devices was housed.