Features of the Darn Tough Women’s Topless Multi Stripe Sock Performance Fit: No slipping, no bunching, and no blisters Fast Action Wicking: Pulls moisture away from skin and fast dryin. All Weather Performance: Cool in the summer, warm in the winter Naturally Antimicrobial: Repels bacteria and odor Merino Wool: The ultimate fiber for breathability and comfort in all conditions True Seamless™: Undetectable seam fusion for an ultra smooth, invisible feel Fine gauge knitting Lifetime guarantee