The Smartwool PhD Hunt Light Crew Sock is lightly cushioned wool sock that's soft and secure. Indestrucawool(TM) Technology is durable and the 4 Degree(TM) elite Fit system adds extra stretch and keeps the socks in place. And, because it's wool, you get naturally moisture-wicking qualities alongside antibacterial assistance. Features of the Smartwool PhD Hunt Light Crew Sock Indestructawool Technology Features a patent-pending construction method for exceptional durability and comfort 4Adeg Elite Fit system provides greater stretch and recovery to keep the sock in place