Socksmith writes, "If you know a barber, we know a pair of dress socks he would love. All of the bamboo socks for men are made using an OEKO-TEK certified process which is completely free of harmful chemicals. On top of that, they are certified organic through OCIA! Super-breathable, antimicrobial and antibacterial!" Sock size 10-13, fits U.S. men’s shoe size 7-12.5. Fiber Content: 59% rayon from bamboo, 39% nylon, 2% spandex.