Harry Potter Slytherin Faux Knee High Socks, Green & Yellow Officially Licensed Harry Potter Merchandise 68% Polyester; 30% Cotton and 2% Spande These Stylish and Comfortable Knee Socks Feature The Slytherin House Colors and House Crest On the Top. Harry Potter Slytherin Faux Lace Up Cuff Knee High Socks Sock Size 9-11; Shoe Size 5-10