The Darn Tough Mountaineering Micro Crew Socks ensure you never need to head for shelter when the conditions take a turn for the worse. Sleet, freezing rain, sub-zero wind chills, snow? More please. Our Mountaineering sock never heads for shelter. If you're out there, this sock wants to be with you. Darn Tough Mountaineering Micro Crew Socks Features Performance Fit: No slipping, no bunching, and no blisters. Fine Gauge Knitting: Unprecedented durability and our unique “put it on, forget it’s on” feel. Fast Action Wicking: Pulls moisture away from skin. Fast drying. All Weather Performance: Cool in the summer, warm in the winter. Naturally Antimicrobial: Repels bacteria and odor. Guaranteed For Life: No strings. No conditions. For life. Merino Wool: The ultimate fiber for breathability and comfort in all conditions.