Our Primaloft(R) Lightweight socks utilize Primaloft(R) polyester yarn to keep your feet warm in a variety of temperatures, all without overheating or being excessively bulky. Features: Calf High - 18cm/7in with seamless toe constructionFabric Content: 45% Polyester, 25% Polypropylene, 25% Polyamide, 5% ElastanePrimaloft(R) polyester yarn offers the best thermal performance to weight in a wide temperature range