The second group had the five twin 5.25-inch guns but did not have the 4-inch gun. The third group's armament was changed due to the shortage of 5.25-inch guns, being armed with eight QF 4.5-inch (113 mm) guns in four twin turrets instead. The 4.5-inch gun was better suited to the primary anti-aircraft role of the "Dido" class. The forward A and B 4.5-inch turrets were mounted on the top of conjoint deckhouses, extending the superstructure to allow the two cruisers to play a flagship role with more accommodation and radar rooms. The high mounting of the 4.5-inch turrets foreshadows the high freeboard and superstructure of the twin 4.5-inch A and B mounting on the County-class destroyers 20 years later. The high rate of fire of the 4.5 turrets and the unique arrangement for a British cruiser of the shell and charge being loaded in a combined case, together with simpler DP twin DCT (Red DCT for A & B and Blue for X & Y), meant that "Scylla" and "Charybdis" were arguably the only members of the "Dido" class that were true AA cruisers. The 4-inch gun was also fitted and the 2-pounder armament was increased from eight to ten.