Fiber contents: 58 percent exclusive thorlon acrylic, 23 percent 4 channel wicking polyester, 14 percent nylon, 5 percent spandex Women's specific design includes extra stretch yarn in the ankle and arch, a smaller heel pocket and a smaller custom toe box for a superior fit Constructed with thorlon fibers for superior softness, resilience, durability, and moisture-wicking for drier, better feeling 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