Darn Tough socks from the Green Mountain State of Vermont! What makes these socks so unique is the fine gauge knitting machines they are manufactured on. With many more needles than is the norm, they produce a highly dense, durable weave that contours to your foot. High density terry loop padding surrounds the entire foot and shin, offering hikers an awesome degree of cushioning while minimizing bulk. 69% merino wool, 27% nylon, 4% Lycra spandex. Merino wool is the fiber of choice for hiking, trekking, and backpacking. Ribbed ankle reduces slipping and bunching. Arch support keeps socks in place, provides extra lift and endurance. Deep heel pocket reduces friction and the chance of blisters. Double nylon in the heel and toe for longer wear.