With 83% Merino wool content, and performance fit system, this full cushion heavy weight winter boot sock has extended durability zones for long-lasting performance. Elasticized arch support and heavy cushioning in the foot-bed to reduce foot fatigue on those multi day adventures. Comfort welt and graduated leg tension for form-fitting stay up all day comfort. Knitted with a 100% unblended RWS certified Merino wool yarn, and then plaited with stretch nylon and spandex during the knitting process for that unmatched comfort, fit, and long lasting durability. Merino wool is highly breathable, thermo-regulating, moisture-wicking, and odor resistant. Designed and manufactured in Canada with Canadian sourced materials. Machine washable for easy care.