The Darn Tough Mesa Crew Charcoal mixes the durable comfort of fine-knit Merino Wool with a pajama-pant aesthetic. The men’s sock includes fine gauge knitting, true seamless fusion, fast action wicking, and is naturally antimicrobial. The classic, versatile height, crew sock is made of 60% Merino Wool, 38% Nylon, and 2% Lycra Spandex.antimicrobial. The classic, versatile height, crew sock is made of 60% Merino Wool, 38% Nylon and 2% Lycra Spandex.