Artist's commentary
Kongou-chan and Nagatsuki-chan in civilian clothes in September
Kongou-chan in civilian clothes in Nakau collaboration is cute, isn't she?
A diligent cardigan Nagatsuki omake manga. (✿´ ꒳ ` )
The commentary mentions Nagatsuki because it applies to the next three pages as well. Nakau is a noodle store chain, which had a collaboration with Kancolle in Fall 2016.