Officially Licensed Nickelodeon Cartoon Socks by Rock 'Em! Your favorite characters and shows on your feet! Step into style. Sock Size Information. LARGE: Large / X-Large also called L/XL = Shoe Size 9-13+. MEDIUM: Small / Medium also called S/M = Shoe Size 6-8.5. SMALL: Youth / Kids also called YTH = Shoe Size 2-5.5.