FoxRiver Outdoor Merino Wool Trailhead Heavyweight Crew Socks 77% Merino Wool, 22% Stretch Nylon, 1% Spandex Made in US Spandex compression arch holds form and adds support Heavyweight socks feature soft Merino wool fibers keep you itch-free while drawing moisture away from your skin The Heavyweight knit cushions your foot on even your toughest treks Fully thermalined construction absorbs Shocks and insulates Reinforced toe and Heel add durability and longer sock life; made in the USA