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!