Anatomically designed and knit to better fit each foot (L/R). URfit™ System provides arch support and memory-knit construction. Vented panels remove moisture and keep you dry. NanoGlide® nylon reinforced toe and heel add comfort and longer sock life. Over-the-calf, medium weight sock. Merino Wool. Fiber content: 40% nylon, 28% Merino Wool, 28% acrylic, 2% polyester, 2% spandex.