The Smartwool PhD Pro Light Crew Sock is a hiking sock with more height to protect your legs without making you too hot. Mesh venting lets your body heat flow without resistance. Indestrucawool(TM) construction Technology makes the sock durable in case of rogue debris. In terms of comfort, it has what you're always looking for in a sock: a cushioned sole, flexible ankle, soft material and seamless toe. All Features combine to create a comfy trekking companion. Features of the Smartwool PhD Pro Light Crew Sock Indestructawool(TM) Technology 4 Degree(TM) elite Fit system with flex zone atankle joint Virtually Seamless(TM) toe Achilles strap provides extra protection andwarmth Premium yarn construction Fabric Details: 62% Merino Wool / 36% Nylon / 2% Elastane