SEAL IN THE HEAT: Stay nice & warm without dealing with uncomfortable bulk. Made out of itch free Merino wool our Castile Light liner crew socks trap heat while treating you to luxurious softness. 65% Merino wool 34% nylon, 1% spandex NATURAL MOISTURE CONTROL: We believe warm feet don’t have to mean soggy socks. That’s why we designed our women’s and men’s sock liners out of the finest wool which naturally moves away moisture to prevent funky feet & blisters. NEXT-LEVEL COMFORT: These merino wool liner socks aren’t just pleasurably soft they also feature our signature flat toe seam. So, whether you are out in the woods, deep in the mountains, or hard at work, you’ll be extra-comfy walking in your boots DURABILITY IS IN OUR DNA: A testament to the legendary Fox River ruggedness. The heel and toe are reinforced with nylon to withstand constant wear and washing, while a flat toe closure technique stretches every way you do without unraveling.