Designed for cold late season activities the Smartwool Trekking Heavy Crew Socks will keep you warm and protected. The Merino Wool blend (80% Merino, 19% Nylon and 1% Elastane) construction is super warm, comfortable and durable. The high percentage of Merino Wool makes these socks moisture-wicking, quick-drying and naturally antimicrobia,l for a fresher and better smelling day. WOW technology reinforces high-impact zones such as the heel or ball of the foot with extra wool, reducing fatigue and abuse an increasing comfort for your feet. The elasticized arch brace ensures a snug fit, while the flat knit toe seam ensures that your days having to deal with uncomfortable toe seams are over forever.