The Darn Tough Merino Wool 1/4 Mesh Running Sock is an ankle-high sock with open-mesh knitting on top that enables your hardworking hooves to breathe. Merino wool pulls moisture away from your skin as you run to keep your foot dry and comfortable. Darn Tough added nylon to these lightweight socks and reinforced the heel and toe to make them tough. Elastic around the arch gives you a snug fit, so your sock won't bunch or wrinkle and give you blisters.