The Darn Tough Mountaineering Micro Crew Socks never heads for shelter. If you're out there, this sock wants to be with you. Sleet, freezing rain, sub-zero wind chills, snow? This sock just asks for more. 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.