These Peakheat work socks use a unique yarn blend of Merino wool and Thermolite® to keep your feet warm during the coldest days without the bulk. Not only are they warm but also built tough for long lasting wear. Unisex fit Reinforced Heel/Toe Shock Absorption Comfort Toe Seam Arch Support Breathable Mesh Moisture Wicking Memory Knit 39% Merino wool, 32% Nylon, 22% Thermolite®, 5% polyester, 2% spandex Style #6630