The Perla-class submarines were the third sub-class of the 600 Series of coastal submarines built for the Royal Italian Navy during the 1930s and named after gemstones. Of the ten boats built of this class, only three survived World War II.
Perla-class submarine (Perla)
The Škoda 10 cm K10 was a 100 mm (3.9-inch) naval gun of the Austro-Hungarian Navy used as tertiary armament on semi-dreadnought battleships and as primary armament on scout cruisers and destroyers during World War I. After World War I, variants of the Škoda 10 cm K10 were widely produced in Italy as the 100/47 series of guns, which served in a number of roles, on a wide variety of ships, with a number of navies.
A twin "Minizini" mount aboard the Soviet cruiser Krasnyi Kavkaz