This turret is the Mk.21 130mm Dual-Purpose Advanced Gun System (DPAGS). It was originally designed for the Admiral of the Templar Fleet of the Grand Armada of the Republic Alexandros L. Seneca-class Heavy Guided Missile-Equipped Gun Cruisers (CGA), though it is planned to be used on other vessels, including the Carolus Rex-class nuclear-powered super battleships and Lietuvos Respublika-class nuclear-powered hybrid aviation super battleships, among other vessels.

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