The Outdoor Sport Medium Crew Sock features SmartWool's 4-Degree Fit System, which secures the sock in place for exceptional performance and fit. The reinforced heel and toe provide enhanced durability for long-lasting wear. The 1 x 1 double-ribbed cuff and flat-knit toe seam help keep feet comfortable throughout the day. This medium, full-cushioned crew sock is made from a rugged blend of 82% New Zealand Zque Merino wool, 17% nylon, and 1% elastane fabric. Made in the USA.