 Leipzig used Krupp cemented armor , while Nürnberg received the newly developed Wotan Hart steel . The ships were protected by an armored deck that was 30 mm ( 1 @.@ 2 in ) thick amidships and an armored belt that was 50 mm ( 2 @.@ 0 in ) thick . The belt was inclined to a greater degree than in the preceding Königsbergs , to increase the effectiveness of the same thickness of armor plate . The sloping armor that connected the deck with the belt was 25 mm ( 0 @.@ 98 in ) thick . The conning tower had 100 mm ( 3 @.@ 9 in ) thick sides with a 50 mm thick roof . The gun turrets had 80 mm ( 3 @.@ 1 in ) thick faces , 35 mm ( 1 @.@ 4 in ) thick sides , and 32 mm ( 1 @.@ 3 in ) thick roofs . They were mounted on barbettes that were protected with 60 mm ( 2 @.@ 4 in ) of steel plating . 
