An improved version of a medium caliber twin gun mount equipped as main armament of light cruisers and training cruisers. <br>The improved version of a naval weapon used on the seaplane sender Nisshin, the Katori-class training cruisers Katori and Kashima, and the light cruiser Yuubari. While not fit for anti-aircraft combat, they are effective as anti-ship and coast bombardment weaponry.