Way back in October, the ladies of f(x) were already endorsing major brand K-Swiss as models just one month after their debut. First came their sporty retro shoot for the 09/10 Winter Collection, a commercial with a preppy commercial & BTS and Christmas greeting. K-Swiss is now back with a new advertisement that reveals f(x)'s maturation since their last endorsement with a cheerful & colorful look. "With f(x)'s fresh and stylish line, we'll reveal a modern style for K-Swiss," a company representative stated. Sulli, who sported long hair for this shoot, has caught the attention of many, even kicking her up a few notches on the search rankings of many portal sites. "Krystal's style, Victoria's style, Sulli's style... we've incorporated everyone's styles into this line," the PR representative continued. "We're looking forward to the interest we anticipate to generate from a younger age group." On February 17, a fresh batch of photos as well as a BTS video will be released. Stay tuned!