Fusion Acrylic Blend: Acrylic blend provides thermoregulation, soft hand feel, and extraordinary warmth to weight ratio Toe Box Oven: Fully wrapped terry loop toe box keep your tootsies toasty Engineered Arch Support: Reinforced arch construction built to give you correct support and eliminate foot fatigue Y-Gore Seams For Dynamic Fit: A Y-shaped seam is knitted into the heel cup to provide you with a perfect fit Air Channel Cushioning: The anatomical cushion design has air channels to keep your feet cool and comfortable Reinforced Toe/Heel: Twisted yarns in toe/heel to provide extra durability Flat Toe Seam: The toe box is linked stitch-by-stitch to ensure a flat look and an abrasion-free experience