Thermal trekking sock made with Merino Wool and polyster fiber, with empty core in order to storge body heat while carring out the thermic compensation process which avoids overheating and sweat.Ideal Use: EBC, Kailash, Trekking, cold-weather travel, mountain trails, long walks, boot wear, winter trips & multi-day outdoor use. Designed for Skiing, Hiking & Winter OutdoorsMaintenance Tips - Hand wash and machine wash are both acceptable, please do not use bleach to avoid damaging the color of the novelty socks for women men