Darn Tough doesnt use strings, but if they did, the Element Micro Crew is first-string varsity all-pro. Easy on the eyes yet loaded with features, this Merino Wool Run sock offers top foot breathability and ultra-marathon durability that wont quit even if you want to. Its adapted tech foot is the secret to crushing your next training block. But keep it hush. Also, we use yarn. A performance fit means no slipping, no bunching, no blisters Runners enjoy Merino Wool's ability to dry quickly and move excess heat and moisture away from feet Materials 55% merino wool, 42% nylon, 3% lycra spandex