These Fox River outdoor socks are lightweight and have an anatomical fit, meaning they are designed to fit the left or right foot. (Don't worry, they're labeled L and R!) The reinforced heel and toe add durability and help you get the most miles out of your socks. These socks feature primaloft and wick dry technology to keep your feet warm and dry. Fox River socks are guaranteed against manufacturing defects for 1 year and are proudly made in America. Specs: 30% PrimaLoft, 29% nylon, 20% merino wool, 11% nanoGLIDE nylon, 8% polyester, 2% spandex