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Darn Tough Thermolite® RFL 1863 Over-the-Calf Ultra-Light Black / Blue


Brand Darn Tough Vermont


  • 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.
  • THERMOLITE®: Insulated material specially engineered to provide warmth and comfort without weight.
  • True Seamless: Undetectable seam fusion for an ultra smooth, invisible feel.


  • Ultra-Light: Our lightest sock for race day or anyone looking for a lighter-than-air feel from a tougher than hell sock.
  • Over the Calf Height: The name says it all. The ultimate height for keeping the outside—out.
  • 51% Nylon, 45% Thermolite Polyester, 4% Lycra® Spandex