Great for all warm weather activities, hiking, biking, trail running and walking. Thin and lightweight, yet very durable.Also works as a liner sock.Full cushion foot decreases foot fatigue.Machine washable and machine dryable. 57% Merino wool, 29% nylon, 11% stretch nylon, 3% spandex. Sock size charts: Small: Men 4-6.5, women 5-6.5. Medium: Men 6-8.5, women 7-9.5. Large: Men 9-11.5, women 10-12.5. X-Large: Men 12-14.5, women 13+. Material: Wool.