Low cut (2.5") fast-drying 37.5 merino wool training sock. Ultra Light, no cushion, mesh instep to enhance breathability, reinforced heel and toe, arch support. 37.5 active particles supercharge wool's natural abilities by attracting moisture while still in vapor form, before it becomes a sweat droplet. Stay drier longer and increase athletic output. Wool 59% Spandex 5% Nylon 36%