The brand named Seishun Konbu is using 2 characters, Misaki Erimo （みさき えりも） and Chishima Kirika （ちしま きりか） both cast as 2nd year middle school students (中学生).
You can buy this konbu online though it is all in Japanese and looks like they are only sending domestically within Japan.
Konbu is an essential part of Japanese diet and is used to make dashi (soup stock). Over 90 percent of konbu in Japan is cultivated in Hokkaido.
All photos from Fujita konbu kakoujyo, sellers of seishun konbu