This set of Calvin Klein 4 Pack Crew Socks for Men is crafted with 100% genuine materials and available in UK size 6.5-11, US size 7-12, and EUR size 40-46. The socks are machine washable and made with a mix of cotton, polyamide, elastane, and other fibers. The black socks consist of 74% cotton, 20% polyamide, 2% elastane, and 4% other fibers, while the black and grey socks are made of 71% cotton, 22% polyamide, 5% polyester, 2% elastane, 75% cotton, 19% polyamide, 2% elastane, and 4% other fibers.