Finally, a lightweight sock that can multi-task. When you infuse polypropylene with Silver Technology, you get unmatched versatility. They repel water, regulate temperature and are reinforced and padded in all the places needed to avoid blisters and bunching. They're great as a hardcore activity standalone sock all year long, and they perform super as a liner in extreme conditions. Made in the USA. Mens shoe sizing- Small(4-5), Medium(5-8), Large(9-12), X-Large(13-15)