Power bands of Lycra hug your entire foot for maximum support. This snug, supportive fit eliminates movement to prevent blisters. Thin flat knit construction takes up minimal room in the shoe. iWick fibers wick moisture to keep feet cool, dry and odor-free. Lightweight mesh encircles the entire foot in two places for better ventilation and breathe-ability. Y-heel construction keeps the sock from sliding into the shoe. The Perfect ToeTM (No irritating toe seam). FEETURES! SOCKS SIZE CHART.   Both mens and womens sizing..see below! SMALL    FITS:  (WOMENS 4-6.5) MEDIUM FITS:  (MENS 6-8.5)  (WOMENS 7-9.5) LARGE    FITS:  (MENS 9-12)   (WOMENS 10-13) X-LARGE FITS:  (MENS 12.5-15.5)