Input (grade 12): During the group's promotions, members Jessica, Tiffany and Seohyun were also featured on a mini-album released by Roommate, a one-man band from Purple Communication. The mini-album was titled Roommate: Emotional Band Aid, and was released on December 1, 2008.
Output (grade 10): A digital EP featuring Jessica, Tiffany, and Seohyun was released on April 2008, titled Roommate.