Contains four 5in./51 gun on open mount. This gun was designed in the 1910s and could be found on US Navy classes of ships built until the late 20s. Battleships: Florida (B-30), Wyoming (B-32), New York (B-34), Nevada (B-36), Pennsylvania (B-38), New Mexico (B-40), Tennessee (BB-43) and Colorado (BB-45) classes. Carriers: Langley (CV-1), Long Island (AVG-1), Bogue (CVE-9), Sangamon (CVE-26) and Charger (CVE-30) classes.Destroyers : Hatfield (D-231), Brooks (D-232), Gilmer (D-233), Fox (D-234) and Kane (D-235. Was in service also on auxiliairies, second line warships,and armed merchanships.