synthetic MADE IN THE USA: Swiftwick socks are made in the USA, an important commitment we make to our customers and local communities. Purchase includes one pair of socks. SIGNATURE OLEFIN FIBER: Made of high-performing, lightweight Olefin fiber that wicks moisture and dries quickly. Abrasion resistant, strong and colorfast. Material composition is 80% nylon, 14% Olefin fiber, and 6% spandex. REINFORCED TOE AND HEEL: Featuring a nylon reinforced heel and toe that provide maximum durability in high abrasion areas. CHANNELED UPPER: Thin channeled upper improves breathability. Y-HEEL CONTOUR AND SEAMLESS TOE: Y-shape stitch creates a contoured heel pocket that moves with the foot. Virtually invisible toe seam eliminates friction in the toebox.