The Urberg Mountain Trail Sock is a pair of sports socks that would be a toasty warm addition to your walking boot. The socks are constructed from a thick wool blend with polyamide and elastane. According to the manufacturer, they are best suited for shell boots with no lining. Theyre guaranteed to fit perfectly! Plus, they were tested on polar expeditions with very positive results. Plus, Urberg donates 1% of its annual revenue to a non-profit organization committed to protecting our planet. With these sports socks, not only will your outdoor adventures be more fun, but youll be protecting the environment as well. A great choice: the Urberg Mountain Trail Sock sports socks.