thorlos Hiking Ultra Lite Crew Socks 77% Polyester, 18% Nylon, 5% Elastane Made in US No Closure closure Machine Wash Ultra thin construction provides supreme moisture management Constructed with thorwick cool fibers for superior moisture-wicking for drier, cooler feet Made in statesville, north carolina, USA 30 day guarantee: Thorlos feel better than ordinary socks. If you do not agree, send the socks and your receipt to Thorlos for a full refund