SockGuy SGX Sock Features The thinnest, most durable, moisture-wicking polypro base to keep feet cool and blister-free Mesh upper for ultimate airflow Arch support so they stay put on your foot Compression-style cuff fights leg fatigue and never falls down Double-stitched nylon heel & toe for durability and longevity Unique Stretch-to-Fit sizing system for a perfect fit on a wide range of foot sizes SockGuy SGX Sock Sizing Small/Medium: Men 5-9, Women 6-10, Euro 37-42 Large/X-Large: Men 9-13, Women 10-14, Euro 43-48